This is an extremely common practice in animation where, to establish a familial relationship, a child looks more or less identical to one of his or her parents. Frequently occurs when a show uses garish or outlandish designs, where subtlety and fine physical detail are already lost, and we need a quick visual aid that other characters may not seem to notice.
This is probably born out of the Economy Cast mindset of a single character for a single role, since we're not given clues to what the other parent might look like and thus shouldn't think about it. Predictably, this trope is less frequent when the child has a non-twin sibling who can't also look identical, although occasionally the difference is to show they're not related by blood.
Often, if a family is the stereotypical four-member "nuclear" one, the son might resemble his mother, or the daughter her father, in an attempt to mix things up. Another common variant is to make the father and the son/the mother and the daughter look nearly identical, but with the other parent's hair or eye color. Also, if there's a Tomboy and Girly Girl (especially if they are sisters), expect that the tomboy will resemble her father more and the girly girl will resemble her mother more.
Some will go as far as to make the parentslook similar. It's usually done innocently, often in children's shows where the offspring are seen first, but the possibility of Incest Subtext can be shady to older fans.
Compare Uncanny Family Resemblance, Identical Grandson. Contrast The Ugly Guy's Hot Daughter, where you'll find yourself relieved that Strong Family Resemblance isn't always the case. A subtrope of this would be Hereditary Hairstyle.
Very common in Dragon Ball. The most obvious example is Goten, who looks (and acts) like Goku when he was a kid; this is lampshaded in the games where he and a younger version of Goku appear. Goten may have initially been created to fill the 'young Goku role' left as the real Goku was too aged and Gohan was evolving into his own character, but that didn't work out too well. Since not every child in the series has such a strong family resemblance, it's also removes lingering doubts that the often absent Goku isn't his father...
Gohan also has some resemblance to his mother Chi-Chi, inheriting her light peach skin tone and some facial expressions.
Similarly, the few times we see Vegeta's father, he looks pretty much like Vegeta with a few minor differences: brown hair, a slightly sturdier build, and a goatee.
In an anime movie, we see Vegeta's great-great-grandson and he looks identical to a young Vegeta (It's unknown if he descends from Trunks or Bulla). And said Vegeta Jr.'s mother looks like Bulma.
Speaking of Bulma, her daughter Bulla takes her looks.
As seen in the pic above: Goku's father Bardock is nearly identical to his son, except for scars and a slight difference in facial shape.
Incidentally, the resemblance is "second son identical to his father": Goku is Bardock's second son while Goten is Goku's second.
More like "second child identical to one of the parents". Bra looks exactly like Bulma, and is her second child with Vegeta.
Interestingly enough, Gohan's hair resembles that of his father's older brother Raditz when it's ankle-length on Namek, though it does manage a Goku-ish shape during the Cell Games.
Or what Gohan's second child, if a son, would look like... Though we do know what Gohan's great-grandson, Goku Jr, looks like: he looks identical to Goku though with his grandmother Pan's eyes.
Apparently this all has to do with Saiyan genes. It's a form of identification to tell the weak Saiyans from the strong ones easily through facial features and whatnot.
Frieza and his father strongly resemble each other as well, though it could be a quirk of their species.
Krillin and Android 18's daughter Marron looked like Krillin with pigtails as a toddler. As a young girl, she resembles her mother. Which raises questions as Krillin's lack of nose is a plot pointnote He uses it and the accompanied lack of sense of smell to beat a stink-villain, Bacterian; Marron has no nose like him as a toddler, but gains one as a young girl.
In Hare+ Guu, Hare looks exactly like his mother Weda enough that the school doctor initially confuses him for a girl. In a huge irony, the school doctor turns out to be his father.
While not very closely resembling her half-sisters at all, Urd of Ah! My Goddess is a dead-ringer for her own mother, Hild. If it weren't for Hild's slight height advantage, different hairstyle, and slightly larger bust they could pretty easily be mistaken for one another.
In Sailor Moon, Usagi and Chibi-Usa are very similar (except for the hair colors), and the few glimpses we get of parents have them looking nearly identical to their daughters. In the manga Minako and Usagi's entire families are copies of each other, which wouldn't be so jarring if the 'newer' plot didn't force Usagi to resemble her mother in a past life, meaning she doesn't look like her modern family at all.
The parody manga Parallel Sailor Moon introduces daughters of the four Guardian Senshi, who look exactly like their mothers and have the same names.
In Please Teacher!, Mizuho and her mother look very very similar. so much so that Kei confuses the two of them on more than one occasion with embarassing consequences.
In Lucky Star, Konata Izumi is basically a clone of her mother, with her father's skin tone and mole. It's obvious enough that the Hiiragi twins mistakes a picture of her parents together for Konata and her dad, and that leads to some interesting questions. The same is true of all the mothers seen in the series. The Hiiragi twins' father gets more onscreen time than their mother, but since all four offspring in their family are daughters, they all resemble the mother.
Ranma ½: Girl-type Ranma, color of hair and eyes aside, is almost identical to her mother. Unfortunately for him, Nabiki decides to point this out at the most inopportune moment, specifically when he's trying to pass himself off as Akane's cousin in order to avoid fulfilling a rather nasty ritual suicide pact.
Subaru and Ginga Nakajima of Magical Girl Lyrical Nanoha look like splitting images of their mother. Subverted when it's later revealed that they were experimental cyborgs that Quint rescued and then adopted partly because they looked like her. Doubly subverted when it's even later revealed that Quint is their genetic mother... in the cloning sense, since the illegal researchers had somehow gotten hold of Quint's DNA and used it to create them.
In a more typical case, Nanoha herself ends up looking rather similar to her own mother Momoko when she grows up.
Lutecia looks very much like her mother Megane, particularly in her hair color and style.
Fullmetal Alchemist: Ed and Al (pre-transmutation, anyway) both look a lot like Hohenheim, especially Ed.
Also Armstrong family males (and some of the women).
In the finale family photo, Ed's and Winry's unnamed son looks uncannily like Daddy, down to the shit-eating grin. Baby Daughter looks to take after Winry, as she has Winry's eye and hair colors.
Akira Maeda from Cromartie High School is "renowned throughout Japan for his startling resemblance to his mother", as it's put in the manga. His friends keep confusing the two of them. They were also played by the same actor in the live-action adaptation.
The Pretty Cure franchise usually features parents who do not resemble their children a lot. While the Cures have obviously Anime Hair, most of their parents look pretty normal, but not hot at all. However, later series feature parents who have also their children's odd hair colors. Smile Precure is the only series who features two youthful mothers who actually resemble their daughters a lot. Yayoi's mother Chiharu and Miyuki's mother Ikuyo, the latter just look like her daughter to the extreme (in the franchise, of course). Later, Rikka's mother Ryoko looks also like the adult version of her.
Said above, other mothers who share the same hair colors with their daughters do resemble them, but usually not that much. You can argue how much mothers and daughters look alike or not.
A very odd case in Suite Precure: Hibiki's father Dan has red hair, while Hibiki herself got her hair color from her mother Maria, but Dan's hair resembles Rin Natsuki's hair a lot who is from a completely different continuity.
Mahou Sensei Negima!: When Negi magically ages himself up, he's indistinguishable from his father, Nagi. When he travels into the magic world, the resemblance is a plot point. Naturally, the strong resemblance, combined with the fact that Negi's mother was never mentioned, spawned a number of Epileptic Trees concerning Negi's possible origin. This was jossed later, when the identity of his mother (Princess Arika) was revealed; personality wise he resembles her quite strongly, although he's much more upbeat. This also played for laughs; Evangeline, who was Nagi's Stalker with a Crush, mistook Negi for his father and tried to get a date out of him.
Azumanga Daioh, the manga, doesn't show us any of the girls' parents (unless you count Chiyo's dad) but in the show, we get a brief glimpse of Kaorin's mother, who is basically a slightly taller Kaorin in an apron. We're also told that Tomo and her father had the same hairstyle at some point.
Rossiu also looks uncannily like the priest of his village at the very end of the series, leading to WMG as to whether or not they're related (it's never clarified in the show either way).
Naruto, especially after Art Evolution, looks just like his father, Minato Namikaze (the 4th Hokage).
Most of the Konoha Twelve look like younger versions of their parents, especially the Ino-Shika-Cho trio. Hinata's mother, who was only shown in a flashback in the anime, strongly resembles her after the timeskip.
In Chapter 498 Naruto meets his mother Kushina and at one point she mentions Naruto has her face and Minato's hair.
Kakashi is said to look just like his father, and indeed, several characters (Chiyo, for example) have already confused the two. For the readers it's a bit harder to tell, since we have yet to see Kakashi's face. The two of them share their hair and eye colour, though,
The Uchihas, especially those whose first names we know, seem to all look the same, to the point that they can only be differentiated by subtle features unique to each individual. Subtract the bags under Madara's eyes, or Izuna's distinct upper lip, or Itachi's tear troughs, and you get Sasuke.
Mikoto Uchiha is literally a female Sasuke with long hair. True to form, she's incredibly pretty.
Shisui Uchiha looked very much like his ascendant Kagami. Their personalities are strikingly similar as well.
Gaara and Kankuro both look a lot like their father while appearing somewhat different themselves; same goes for Temari and their mother.
Kiba Inuzuka bears a strong resemblance to his mother, Tsume. Interestingly, his older sister Hana looks nothing like Tsume, and is clearly lacking a lot of the feral-looking Inuzuka traits present in her mother and brother. It makes one wonder what Kiba and Hana's absentee father looks like.
Hyuuga tend to have strong resemblance, especially when their hair is long. Hanabi looks like a young Hinata with longer hair, Neji resembles his father (and Hinata), and most other relatives look quite alike.
In Detective Conan, Yuusaku Kudo and his son Shinichi look almost exactly the same (Yuusaku has glasses and a funky mustache, Shinichi has a cowlick and a pointy rat-tail). The physical similarities went off the ceiling when we saw Yusaku at age 20◊: if his face was rounder and his eyes were bigger, he'd be an exact clone of Shinichi.
The same goes for Kaitou KID and Shinichi; even though nobody knows whether or not they're related.
Actually, a hugeplot point in a case of the fifth season. The detective Yusuke Sakata, whose father died in strange circumstances 20 years ago, confronts a Serial Killer. Much to his shock, the Serial Killer starts referring to him as "Instructor Inaba" and babbling in horror about how "the prank went too far". That obviously, refers to the death of Sakata's dad Inaba, which he and other five people caused through a Deadly Prank. Yusuke, who had become a policeman to investigate what went on with his father, became a Serial Killer himself, catching and murdering the other culprits while keeping the other murderer alive and hidden while planning to kill him last and frame him for all the deaths.All to punish those who robbed him of his dad when he was a little boy. And on the other hand, this was also Yusuke's perdition: at some point Heiji and Conan saw a picture that included all of the victims plus other two persons whom Yusuke had still not killed... as well as Inaba himself. This lets them notice how physically alike Yusuke and Inaba were, identifying Yusuke as the killer.
Brilliantly carried off in Neon Genesis Evangelion. Initially you can't see any resemblance between Shinji Ikari and his father Gendo Ikari — but then in episode 5 Shinji briefly puts on a pair of Gendo's old glasses, and later in episode 21 you get to see what Gendo looked like when he was younger. The resemblance is disturbingly striking, without the two of them looking like lazily designed age-clones.
Shinji also resembles his mother Yui. It helps Shinji was designed to have a female looking face.
Ritsuko Akagi, as it turns out, shares quite a resemblance to her mother Naoko, as seen in episode 21 where we learn that she wasn't a natural blonde - save for her characteristic mole on her cheek, Ritsuko would look a lot like her mother when she's older if you were to superimpose her original hair colour over her current one. Much like the Shinji-Gendo similarity above, this is intended to be a display of Not So Different, and rather disturbingly so - even her hair and clothing styles become more like Naoko's as she gets older, not to mention her sleeping with Gendo just as her mother had done.
And of course, in the most disturbing example and the most loose definition of family resemblance, Rei Ayanami shares a striking resemblance to the woman from whom she was at least partially cloned - Yui Ikari, Shinji's mother. Which makes her Shinji's half-sister... sorta.
The way the nations in Axis Powers Hetalia are related can be a little confusing, but England and Sealand are most certainly related. Sealand looks like a younger, more hyper England.
If Germany were to grow his hair long, he'd be identical to his ancestor, Germania. His older brother, Prussia, also shares a certain resemblance with them, though his eye and hair color sets him apart.
Muss up Germany's hair and he ends up looking just like Prussia in the webcomics. Similarly, slick Prussia's hair back and he looks like a slightly older Germany with white hair and reddish eyes.
Depending on whether or not you believe that Germany is related to the Holy Roman Empire, or is the Holy Roman Empire, you can't deny that HRE looks like a younger Germany, and that Germany bears a resemblance to the sketch of teenage HRE when his hair isn't slicked back. Meanwhile, in North America, Canada and the U.S. look identical to the point that poor Canada is often mistaken for his more noticeable brother. Fanon has it that they're twins. South Italy looks to be a darker, meaner, and slightly taller version of North Italy, and is otherwise completely the same. Several of England's relatives apparently sharehis eyebrows.
Don't forget that both Italies strongly resemble their grandfather Ancient Rome. Both inherited the curls, Veneziano got his smile and brown eyes, and Romano got the olive complexion and dark hair.
Subverted with Switzerland and Liechtenstein. They're not exactly siblings (more like adoptive sibs, though it's easy to infer they're at least distantly related due to being Germanic), but they look almost exactly alike. And even more when Liech cuts off her braids.
Also subverted with Cyprus and Greece. He does look like a younger and slimmer Greece... but lacks his trademark Idiot Hair.
This is the case for the Laforets in Baccano!, where you can probably pick out one of them from a sea of Loads and Loads of Characters on the basis that they're all nearly identical to their father, Huey.
One Piece: Usopp and Nico Robin look very much like their parents when they got older. Usopp a combination of his mother and father's traits (long nose, tan skin, hair) and Robin a spitting image of her mother save for the black hair (her mother's is white).
Ciel from Black Butler already looks almost exactly like his late father, Earl Vincent Phantomhive, and will definitely be a carbon copy of him once he's older. He was shown as an adult in the 'Ciel in Wonderland 2' OVA and the resemblance was striking.
And considering Sebastian has taken the appearance of Earl Phantomhive, except for the eyes, this could raise some interesting questions when he's older.
Prince of Tennis. Kaoru Kaidou looks almost identical to both his younger brother Hazue and his father Shibuki, with the two of them essentially being older and younger versions of him. It's actually kind of creepy... and fucking hilarious.
The notes to Shin Tenipuri make the resemblance between Kaoru and Hazue even stronger since Hazue plays tennis too and will apply to Seigaku Junior High once he's old enough, meaning that he now actively aims to be more like his older brother.
Kunimitsu Tezuka looks a lot like both his father Kuniharu and his grandfather Kunikazu in the manga. Much more the latter than the first, though, as Kuniharu is a Nice Guy but both Grandpa and grandson are The Stoic.
Though more subtle, Ryoma definitely shares his father's eyes and intensity.
Pretty much the same case with Joey Jones from Heroman, except unlike with Mizuho's case, Joey's looks aren't lampshaded at all.
In Fruits Basket, Akito and Ren look almost exactly the same — except for Ren's long hair, and um...assets. Also, when we get a short glimpse of Shigure's parents he looks exactly like his mother.
Whether Yuki wants to admit it or not, he does look like his elder brother, the only differences being their eye and hair colors.
In Game X Rush, Memori is an almost exact younger male clone of his mother, to the point where Ken mistakes the latter for the former.
Souma Saiki of Sakura Gari looks like his dead beautiful mother, Abigail, to the point where all he has to do is grow out his hair and wear her shawl to look exactly like her.
The Babies Ever After scene at the end of Digimon Adventure 02 played this unsettlingly straight, right down to the last child. Between that and the conspicuous absence from the reunion of any spouses who aren't former Chosen Children, it's a popular snark among fans dissatisfied with the ending to suggest that they all just cloned themselves.
Nabari No Ou: Miharu and his mother, Asahi. To the point that most non-fans simply assume that the two on this volume cover◊ are Miharu and his own reflection.
In Bakuman。, when Akito Takagi and Moritaka Mashiro look through a yearbook that Moritaka's uncle Nobuhiro "Taro Kawaguchi" Mashiro had, they realize that Miho Azuki's mother, Miyuki Haruno, looks quite a bit like Miho did when she was in high school.
Mirielle Bouquet of Noir looks almost exactly like her deceased mother, Odette, and this winds up being a plot point later.
In Stitch!'s reunion episode with Lilo, it's revealed that the series was a Time Skip all along and Lilo had an identical looking daughter in the time that's passed since they went their separate ways.
Even at thirteen Black Star resembles his father rather strongly, although this flashback was based on Sid recalling what White Star was like because his son's behaviour had become so similar.
When he isn't sporting his trademark Slasher Smile, Kishin Asura's resemblance to his little brother Death the Kid is startling. This is justified since both of them are actually "fragments" of Shinigami that he removed from himself. We never see whether Shinigami himself is capable of adopting a similar 'human' look.
Victorique of Gosick is so identical to her mother that just wearing a different hat is enough to throw people.
Almost everyone in the Oomaeda family looks similar to one another. Played for Laughs since they're almost all Gonks. Only one of the sisters doesn't look like them — and her brother thinks she's ugly!
Ichigo's sister Yuzu looks very similar to their mother Masaki. She's the only sibling who takes after a parent in looks, however.
Ichigo grealty resembles his cousin Kaien Shiba, through his father, Isshin Shiba.
Uryuu looks very much like his father, and even inherited his father's blue eyes. Given how ridiculously young his father looks, the pair could pass for non-indentical twins rather than father and son. However, we later get to see his mother Kanae and learn that he inherited her color scheme (black hair and dark eyes), and some of his softer expressions make him look like her instead.
Shuichi from Wandering Son looks a lot like her older sister, Maho. When she grew her hair out into a bob they looked near identical. Makoto also looks a lot like his mother.
Yukari from Family Compo resembles her dead sister quite a lot. When she asks her nephew to move in with her family, he's captivated by their resemblance.
In Gakuen Babysitters, Ryuuichi and Usaida, lampshade Kamitani's strong resemblance to his mother, who shares the same eyes and hairstyle as him.
When returning to her home in Osaka in Burn Up Excess, Maya Jingu visits the memorial shrine to her mother—whose photograph looks exactly like her, albeit in a gangster kimono with tulip yakuza tattoos. It helps that the late Jingu was probably not much older than Maya was, and is grinning gunslinger in the portrait.
Extremely strong version seen in Upotte, with Jisuri and her sisters Empi, 33, and Gossan. This is because almost all of Heckler & Koch's product line during the Cold War was derived from the G3 battle rifle (the HK33 is a G3 in 5.56mm, the MP5 is a G3 shrunk into submachinegun size firing 9mm, the HK 53 is essentially an MP 5 that fires 5.56mm...)
In Vampire Knight Yuuki is nearly identical to her mother Juuri to the point that Rido wants to use her as a replacement for Juuri, his sister who he was in psychotic love with and Kaname looks almost exactly like Haruka, their father. But then again, this is actually more a case of Haruka being an Identical Grandson, because Kaname is really The Ancestor and Haruka his great-grandson. This is somewhat justified in the fact that their parents were siblings as well, and given that their family tree doesn't fork for many generations, genetic traits would be passed down far more obviously.
V.B.Rose: The Arisaka gene is so strong that the males look so much like each other that their mothers struggle to find remnants of their genes in their children.
In Yotsubato, Miura looks exactly like her mother. This is lampshaded by Yotsuba and later by Mr. Kowai and Jumbo. Miura disagrees.
In Rosario + Vampire, Kurumu, Mizore and Yukari look very similar to their mothers. The manga shows that Tsukune got his face from his mother. The most bluntly example is Outer Moka who looks exactly like her mother Akasha Bloodriver. Justified, Outer Moka is a personality created by the rosario which is invented by Akasha to protect Inner Moka. And thanks to Art Evolution, Inner Moka looks now very similar to her outer personality and her mother.
Moka's older half-sister looks very similar to her mother Gyokuro, just having longer and curled hair and not having an evil expression in her face. However, this trope is inverted with Kokoa, Gyokuro's second biological daughter. Kokoa has red hair, light skin and (for some reason) Green Eyes, she looks nothing like her mother or her father who has black hair.
In the original Vampire Hunter D movie, Count Magnus Lee is impaled by D in the final battle. As Lee is dying, he glances at a portrait of the Vampires' Sacred Ancestor Count Dracula and notices D's uncanny resemblance to it. Lee spends his last moments asking D if he is related to Dracula.
In Sakura Trick, Mitsuki is just an older Yuu with long hair and glasses. Same hair color gradient, same eyes, she even has identical flowers in her hair. Lampshaded by Haruka in episode 5a, but Haruka didn't notice... Mitsuki is crushing on her just like Yuu does.
Mary is almost identical to her mother Shion, aside from slightly different colouration (pink eyes instead of red, white-blonde hair instead of silver-white) and her Blinding Bangs. Her facial structure (in the anime at least) is nearly identical to that of her grandmother, Azami. All three also share a Hereditary Hairstyle, which is used to identify them as Medusae.
Ayano and her mother Ayaka both look very similar (hair and eye colour and facial structure, mostly), only aided by the fact that Ayano wears the same hair clips after Ayaka dies.
Thomas Wayne looks exactly like his son, except with a thick moustache. In The Dark Knight Returns Bruce grows a moustache and looks like an older version of his father, until he shaves it off.
Superman's alien father Jor-El also looks exactly like him (down to the curl Depending on the Artist) and was a young man when he sent him to Earth. In Smallville this was reflected by having Clark's actor Tom Welling play him in flashbacks, though an older actor portrayed him in later episodes.
Sarah Stacy, the identical daughter of Spider-Man's Gwen Stacy. It led to intense squick.
And in most Elsewords where he's a father, Peter's children end up looking a lot like MJ or Gwen. The exception being Spider-Girl, where May looks like both of her parents (and has her Aunt May's eye color!). The trope's played straight with BenReilly's son, instead... although somehow only MJ has noticed the resemblance.
This continues to the Scarlet Witch's 'children', Wiccan and Speed, who are (male) Expies of Wanda and Pietro respectively, down to powers and costumes.
The artists for Archie Comics apparently strongly support this. For example, whenever Betty fantasizes about her and Archie being married with children, their kids look like miniature clones of them. They don't even bother giving the son(s) their mother's hair color.
Even the company's Sonic the Hedgehog title bows to this. Sonya and Manik, Sonic and Sally's future children who appear in flashforward stories/scenes, look exactly like their mom and dad, even though their parents, being of different species, would be more likely to have "mutant hedge-squirrel babies". It's to the point that in Sonic Underground, Sonic, Sonya, and Manic are triplets - practically identical.
Lucky Luke: The Dalton brothers are identical except in height, and their resemblance to Ma Dalton is so strong that the shorter brothers can pass as her just by shaving and putting on a dress.
Astérix and Obelix look exactly like their fathers, right down to the hairstyle, as revealed in Asterix and the Actress. In a short comic in Asterix and the Class ActFR Astérix et la Rentrée Gauloise, Goscinny and Uderzo run into Obelisc'h, who shows them a family tree tracing all the way back to his famous Gaulish ancestor; excepting clothes and hairstyle, every branch looks the same.
Additionally, in Innocence Lost and Target: X Sarah and her sister, Deborah, look very much alike (and in the former case, it would have been almost impossible to tell them apart in scenes they share with each other if not for Debbie's short-cropped hair). As a result, Laura also bears a very strong resemblance to her "aunt" Debbie. And then they go and avert it with Debbie's daughter Megan, who looks nothing like her mother, aunt or "cousin."
In Preacher, Jesse Custer strongly resembles his father John Custer, and not just physically. One of John's old war buddies during the Vietnam War briefly mistakes Jesse for his father when Jesse pays him a visit.
In Ah Archfall, Lind's mother is basically a slightly taller, older and more muscular version of her daughter, with a scar and longer hair.
Almost all 'next generation' or 'remote descendant/ancestor' fanfictions in whatever fandom use this.
Itachi Van Alstyne in White Rain looks exactly like his deceased father Uchiha Itachi, something that makes his uncle Sasuke very uncomfortable. The younger Itachi's little sister Rina on the other hand is a dead ringer for her mother Lucia. In terms of personality and genius, she's exactly like her father Uchiha Itachi.
The Twilight Child: Twinkle is noted to be almost physically identical to her mother, aside from having different mane, eye and fur colours, and being ever-so-slightly taller than she was at her respective age, as well as not sounding the same. Oh, and not having wings.
Noted to be a recurring trend with the future Pinkie Pie's children, all of whom have their mother's pink curls. Even the ones that are adopted.
Films — Animated
In the Disney film Meet the Robinsons, Wilbur is virtually a male clone of his mother, Frannie.
On that note, almost every (biological) member of the family sports the "family cowlick"...on both sides of the family. That's convenient.
Marie from The Aristocats basically looks like a younger version of her mother, Duchess.
According to Pixar, the redneck boy that attacks Randall Boggs in the trailer home at the end of Monsters, Inc. actually has the same model as the animatronic boy in the training room at the very beginning of the film. Also, said boy's mother is essentially another model of the boy, but with a bun placed on his/her head.
In the sequel, Melody looks like an ideal blend of her parents: she has Ariel's features and Eric's color scheme.
The Queen (Rapunzel's mother) from Tangled looks just like an older version of Rapunzel, but with brown hair. The resemblance is further highlighted once Rapunzel's hair turns brown; they look so alike that, when Rapunzel reaches for her long-lost family, just by looking at her the now brunette and shorthaired self the Royals recognize her as their daughter. A very heartfelt group hug follows..
In Rise of the Guardians, when Jack Frost gets the memories of his former life back, we can see that his sister looked a lot like him before his death.
In Disney's Tarzan, the titular character is the spitting image of his biological father - apart from the crazy facial hair and lack of dreadlocks, of course.
In Frozen, the Queen of Arendelle's daughters look just like her; Elsa in particular, but with platinum-blonde hair instead of dark brown.
Films — Live-Action
In Snow White: A Tale of Terror, Lilli looks so much like her mother as to be a symbol for her continued lingering presence in Frederich's heart.
Fredo, the weakest of Don Vito Corleone's sons in The Godfather ironically has the closest physical resemblance to him.
Peter Jackson's Middle-earthuniverse has Thranduil and Glóin, who very much resemble the two Fellowship members Legolas and Gimli, respectively.
In Kagemusha, Takeda Shingen's brother Nobukado bears sufficient resemblance to the great warlord that he has impersonated him in the past. However, he manages to find a thief who looks even more similar to Shingen, who becomes the titular impersonator.
Jim Kirk in the new Star Trek film bears such a strong resemblance to his father that some viewers initially mistook George Kirk for his son.
Ladies of Fleur Delacour's family, thanks to a veela grandmother, are all blonde, willowy, and gorgeous (leading to much speculation of what Bill Weasley and Fleur Delacour's daughter will look like).
The Malfoys are remarkable. They are all pale and blonde - even Narcissa Malfoy née Black, and is actually related to her husband since pureblood wizards are pretty much all distant cousins on some level.
Thow in Bellatrix and Andromeda.
Tom Riddle resembles his father.
Dumbledore and his brother look alike.
Though the Epilogue doesn't go into detail, it is implied Harry's middle son Albus Severus and Malfoy's son Scorpius look exactly like their fathers. All we know about Harry's other kids is that they do not have his Green Eyes.
In the first book, it is all but stated that the Abhorsen have the colour drained out of them by walking in Death, with the changes noted in Sabriel by the midwife. Of course, that doesn't explain Lirael.
Henry from The Time Traveler's Wife is noted to look a hell of a lot like his mother. Despite her status as a mom, this doesn't work as well for him as one might think as it's very difficult living with a father trying desperately to forget his wife's death when you constantly remind him of her.
And then there's Alba, who looks exactly like Henry. Which, this being Niffennegger, is history repeating itself; Alba reminds Clare painfully of Henry after his death.
The youth's face had haunted me. Where had I seen him before. There was something strangely familiar in every line of him; in his carriage, his manner of speaking, his gestures. I could have sworn that I knew him, and yet I knew too that I had never seen him before.
In Kushiel's Legacy books, innumerable instances: the entire House Shahrizai has unusually dominant genetics, coined the "unmistakable stamp", House L'Envers has violet eyes that show up with alarming frequency, and the two princesses look like their parents, but with the eye colors swapped.
In the Gemma Doyle Trilogy, Gemma has enough of a resemblance to her mother to really freak out multiple characters.
In A Song of Ice and Fire, a member of any given noble family is immediately identifiable by various distinct features. The Targaryens all have violet eyes and silver hair, the Lannisters are all blond(e) with Green Eyes, the Tullys all have auburn hair, the Baratheons all have thick black hair, the Manderlys all resemble walruses, the Mormonts and the Umbers all look like bears, the Florents have huge ears, I could go on. This becomes a massive plot point early on: Whenever a Baratheon has a child with a Lannister, the child always inherits the Baratheon black hair. The Baratheon king's bastards all have his black hair. But the children that the king's Lannister wife has given birth to? All blonde. Guess why.
Straighter examples exist with specific characters - there is an astounding number of the younger generation who resemble older ones. Sansa is said to be the spitting image of her mother Catelyn, her sister Arya really resembles her aunt Lyanna, Joffrey is stated to look a lot like his uncle/father Jaime, his little sister Myrcella is also said to look like their mother Cersei, Robert's little brother Renly and bastard son Gendry both strongly resemble him, Jon Snow is said to have the "classic Stark look" like his presumable father Ned did, etc. One of the reasons Catelyn resented Jon was because he looked more like Ned's son than any of the sons she bore him since Robb, Bran and Rickon inherited more of her features.
Oliver Twist has the titular character as a gender flipped version of Agnes, his mother who fell victim to Death by Childbirth. In fact, this VERY important in-story: when Mr. Brownlow sees Oiver next to a portrait of Agnes that he keeps in his Big Fancy House, it's one of the first clues on Oliver's true identity as the long-lost son of Agnes and of Brownlow's dead best friend, Edwin Leeford, the one who painted said portrait in the first place.
In L. Jagi Lamplighter's Prospero's Daughter trilogy, Theo is in fact taken for his father by his own sister. He had after all stop using magic to keep himself from aging. Caurus realizes he's not Prospero only by his aura — whereupon he deduces that it's a seeming and an imposter, and Mab has to throw himself between them to keep him from attacking.
The Ashkevron family in the Heralds of Valdemar series. One character even comments, "The Ashkevron family look tends to breed true, and when it doesn't, the poor thing generally runs off to Haven."
Once Thomas reveals to Harry that they're related, Harry frequently compares and contrasts their looks. Nobody else seems to notice, not even Harry before he found out.
Harry notes that all of the Raiths are impossibly beautiful, and at least somewhat similar. That subconscious awareness saves Murphy from being Fed on at one point. Recurring examples: contrasting Thomas and the reigning Lord Raith, and comparing the Raith sisters.
Maggie Dresden looks a lot like her mom, Susan Rodriguez.
Molly Carpenter takes after Charity a lot. In more than just looks.
Murphy's sister looks a lot like her.
Harry notes that under their different outfits, the Queen of Summer (Titania) and the Queen of Winter (Mab) look virtually identical, so much that they might be twins. He comes to the same realization later, with Maeve and Sarissa.
He started, and after having attentively examined my features, raised me from the Ground, and throwing his Grand-fatherly arms around my Neck, exclaimed, "Acknowledge thee! Yes, dear resemblance of my Laurina and Laurina's Daughter, sweet image of my Claudia and my Claudia's Mother, I do acknowledge thee as the Daughter of the one and the Granddaughter of the other."
In The Shamer Chronicles, Davin and Melli have the same pretty faces and auburn hair as their mother, Melussina, and Davin is said to share her elfin build as well. Dina, however, is the splitting image of her father Sezuan with her black hair and green eyes.
The Everdeen family seems to have this in The Hunger Games: Prim has blond hair and blue eyes like her mother, while Katniss looks like her father. When Katniss and Peeta have children, one has Katniss' hair and Peeta's eyes, while the other has Peeta's hair and Katniss' eyes.
In Doctrine of Labyrinths Felix looks so much like a male version of his mother that he half doubts he had a father at all. The resemblance is so strong that a straight man who never got over the mother ends up hitting on him, which Felix finds insulting and creepy. Before that, there is also a very strong resemblance between Felix and Mildmay. The red hair - very rare in Melusine - is a huge clue that they're related.
Dinosaurs did this with the daughter resembling and acting like the father and the son resembling and acting like the mother. The third child didn't act or look like anyone in the family; in one episode, it was revealed that he was Switched at Birth, ending up in a "Family is the people you love" Aesop and a parody of the Reset Button, with the doctor who confirmed the switch jumping out of a cloud and proclaiming "Science was wrong!"
Occurs on Glee. Thanks to actresses Lea Michele and Idina Menzel looking near-identical, no one bought that Shelby was just the director of Vocal Adrenaline and not Rachel's birth mother. "Dream On" finally confirmed it.
It's possible that the only reason Jonathan Taylor Thomas was hired for Home Improvement is that he looks so similar to Tim Allen.
Along similar lines, it's been openly stated that the role of Niles Crane in Frasier was created specifically because a casting director noticed that David Hyde Pierce looked and sounded like he could be Kelsey Grammer's brother.
Red has a pretty good resemblance to her mother, Anita.
Actress Andrea Parker on The Pretender played both Miss Parker in real-time and her mother Catherine Parker in flashbacks.
One episode of Quantum Leap has Sam leaping into himself as a teenager. Scott Bakula played Sam AND his father in the episode.
On M*A*S*H, Radar received a home movie from home. In the film, his mother is played by Gary Burghoff.
On The X-Files, the younger CGB Spender is played by the same actor who plays his son, Jeffery Spender. CDB Spender is also Mulder's biological father, and oddly, the two could plausibly pass for father and son.
On Highlander, if an Immortal meets someone he knew in a previous identity, he'll at least imply that he's the son or grandson of the person s/he knew.
Arlo from Arlo And Janis and his son look nearly identical.
In Blondie, Dagwood and his son Alexander look like identical twins. On the other hand, his daughter Cookie looks a lot like her mother Blondie, the only real difference being their hairstyles.
For many years the Bumsteads' dog, Daisy, had a litter of lookalike pups running around. They were phased out without explanation in the '70s, mainly because cartoonist Dean Young was sick of having to keep drawing them all.
Jon Arbuckle from Garfield resembles both of his parents while his brother Doc Boy looks like his father.
Although the characters in Peanuts have Only Six Faces, only the Van Pelt family (Lucy, Linus and Rerun) have half-circles around their eyes all the time.
Linus and Rerun especially; aside from height the only difference between them is that Rerun's hair is sort of flatter. It can be hard to tell them apart, at least in the later strips when their ages are fairly close.
Popeye bares a striking resemblance to his father, Poopdeck Pappy. Pappy even took advantage of this on a few occasions by shaving off his beard to play tricks Olive. They both seem to get their looks from Popeye's grandmother.
Sephiroth takes strongly after his "mother", Jenova, in Final Fantasy VII: Both have platinum hair and giant, scythe-shaped forelocks. Somewhat inverted, as Sephiroth was mistaken about being descended from the Cetra. Not only is Jenova his genetic donor, not his actual mother (Lucretia was the surrogate), Jenova is a mimetic creature who took on the shape of the Cetra to destroy them.
The same goes for Sephiroth's father, Professor Hojo, who also sports long hair with antennae (at least in his PSX incarnation).
N and Ghetsis in Pokémon Black and White. A sage of Team Plasma suggests that they may not be related, and the sequel games confirm it.
The mother of the player character from the same game practically looks like an adult version of Hilda, the female protagonist.
Pokemon in general invokes this with the parents. Ethan and Kris look like their Gen 2 mother, and Lyra looks like the remake redesign of her. Dawn looks like a younger version of her mom with longer hair, and Lucas looks like her but with a darker shade of hair. May looks like the Hoenn mother and Birch, and Brendan possibly looks like Norman.
In Diamond and Pearl, the rival, Barry, looks quite a bit like his dad Palmer.
Bowser, the arch Nemesis of Mario from the Super Mario Bros., has got eight children. Seven don't resemble him that much. But his youngest, Bowser Jr. might as well be a clone of him. He looks absolutely identical to his father's younger self from the Yoshi games, or Mario and Luigi: Partners in time. He's also got the same personality.
Rosalina actually resembles her dead mother as revealed in the subplot of Super Mario Galaxy.
Potentially subverted in Star Ocean: Till the End of Time, where Fate and Maria look strikingly alike but the plot only tells us they went under similar 'treatment' as kids. Whether they were siblings seems to be a (deliberately?) hanging detail, although they do have an potential ending together.
Revolver Ocelot of the Metal Gear series looks more like his mother The Boss/The Joy when he's younger and more like his father The Sorrow when he's older.
Knights of the Old Republic has Carth Onasi and his son Dustil: it's patently obvious they decided to save themselves some development time, removed the permastubble from Carth's facial texture and called it a day.
Bubble Bobble series: Some characters in Bubble Symphony, as seen in its intro, look the same as those in Rainbow Islands and Parasol Stars with different hair colors, as if it wasn't confusing enough.
Harvest Moon: Tree of Tranquility/Animal Parade does this for some of the rival kids and your own children. While some of the rival kids (like Heath and Angie) have a plausible combination of their parents' features, others are... less subtle. Vivian◊ especially is more or less her father◊ in miniature, only with longer hair. Your own kids look exactly like you, only (in Animal Parade) with your spouse's hair and eye color.
A milder example is in the A Wonderful Life series, where your child always inherits their hair and eye color from whoever you marry. In the girl version, at least, this troper recalls Takakura mentioning that your son is "the spitting image" of your husband.
This◊ is Isaac, the hero of the first Golden Sun. This◊ is Matthew, his son and the hero of the DS sequel Golden Sun: Dark Dawn, which takes place thirty years later. "Spitting image" doesn't begin to cover it; fans initially assumed Matthew was a redesign. Hilariously, the one character in Dark Dawn who comments on Matthew having a resemblance to a relative compares him to his mother (Briggs never met Isaac).
This is also present to a lesser extent with Garet◊ and Tyrell◊, another father-son pair.
Also, Alex and his bastard son Amiti. Noted by NPCs enough times that by the end of the game, the only person who doesn't seem to realize this is Amiti himself... and even he's starting to catch on, if you read his mind right after the final battle.
While it's not as extreme as Matthew or even Tyrell, both of Mia's children bear a strong resemblance to her. This led to some confusion with her son. Notably, Rief also resembles Amiti.
Comparing character portraits from The Lost Age with Dark Dawn, little Himi in the latter is a dead ringer for her aunt Uzume in the former. We might as well call Dark Dawn "Golden Sun 3: Attack of the Clones".
Azimuth: Ask yourself this: how relevant is the past when it can be changed? Your father would have said, "Not very." Ratchet: That's him.
In Mass Effect 2, Samara and her daughter, Morinth, are completely identical in appearance. This is to Morinth's advantage if you decide to recruit her; she is able to perfectly impersonate her mother, with only Kasumi (and, of course, Shepard) ever finding out the truth.
Bayonetta is implied to look exactly like her mother, down to her outfit of choice.
In Tomb Raider: Legend, we get a look at Lara Croft's mother Lady Amelia Croft, and hot damn now we know where Lara gets her good look from. Amelia is basically a more dignified, less action girl-looking Lara.
The Devil May Cry series has Sparda, twins Vergil and Dante, and if you tilt your head and squint a little, Nero.
Tekken frequently uses this trope, the most obvious being Kazuya Mishima and his son Jin Kazama. Jin differs from Kazuya only because he has a fringe like his mother Jun, as well as being more slender and with slightly finer features than Kazuya.
Retroactively, this can now be applied to Jun and Jin. Originally, Jin more closely resembled his father than he did his mother (to the point that many thought Jin in T3 was a younger Kazuya), but as of Tekken Tag Tournament 2, Jun's facial features better match those of her son.
Alistair of Dragon Age: Origins has a face very similar to that of his half-brother Cailan, as lampshaded by Anora, who is uncomfortable with the idea of marrying Alistair, because he looks so much like her dead husband.
Between the two Fire Emblem Elibe titles, Eliwood and his son Roy in their teenage years (Eliwood at 17, Roy at 15) look disturbingly similar to the point of near-identicality; it doesn't help that they even wear almost the same clothes and it takes looking up their full official artwork to see any significant difference between them. Pretty much the biggest difference is that Eliwood was thinner and wore longer sleeves, neither of which can really be gleaned from ingame appearances.
Interestingly subverted in the case of Roy's best friend Wolt... whose design, first seen in Fuuin, actually served as basis for the three guys that his mother Rebecca can marry in Rekka. Looking at his in-game appearance and checking on his dialogue, the boy has: the haircut and fighting style of Wil, the hair color and personality of Lowen, and the eyes and facial structure of Sain.
Fire Emblem Tellius also has this with Ike, Mist, and Soren. Ike and Mist both resemble their same-sex parent while inheriting the opposite-sex parent's hair color. Soren looks like a younger, male version of his mother, Almedha. A whole game before Almedha was even introduced, it was obvious that Soren had a very strong resemblance to Kurthnaga, the prince of Goldoa, and Rajaion, Ena's fiancé, both of whom were revealed in the next game to be Soren's maternal uncles.
In Fire Emblem Genealogy of the Holy War, Ares and his father Eldigan may as well be identical twins wearing different armor. Likewise, a shorter hairstyle is the only noticeable difference between Larcei and her mother Ayra, while Ulster is basically a genderflipped and shorthaired Ayra. Even more so, the grown-up Prince Shannan looks disturbingly like his Disappeared Dad, Ayra's older brother Prince Mariccle. Several other characters also have an uncanny resemblance to the legendary Crusaders that they descended from.
In Fire Emblem Awakening, Princess Lucina basically looks like a genderflipped, long-haired version of her father Chrom, no matter who her mother is. Similarly, out of Chrom's other prospect children, Olivia's son Inigo and Sully's daughter Kjelle will physically resemble Chrom the most. Whereas Miriel's son Laurent also looks a LOT like his mother, save for the hair color.
Also Morgan doesn't necessarily look super similar to his/her parent The Avatar... but if you choose the youngest built for the Avatar parent and give them short Messy Hair, then Morgan will look like a borderline clone of the Avatar him/herself. Additionally, a female!Morgan mothered by Sumia looks basically like a younger, short-haired Sumia.
In what is part this trope and part Uncanny Family Resemblance, in Back to the Future: The Video Game, Marty runs into his grandfather, Artie McFly, who looks and sounds just like George McFly (both being based on Crispin Glover's performance in the film). Artie's father, William, is once again played by Michael J. Fox, who had previously portrayed him in a photo shown in the third film (even though Marty himself is actually voiced by AJ LoCascio). This leads one to believe that if the pattern continues, since Marty's son will end up looking like Michael J. Fox, his grandson and great-grandson will look like Crispin Glover, and so on. Also, Kid Tannen is basically just Biff with a moustache and zoot suit.
Suikoden V gives us the main character, the Prince of Falena, who really takes after his mother, Queen Arshtat. Skald Egan, your grandfather mentions this when you meet him. Sialeeds, Arshtat's sister, also looks very much like her after she joins the Godwins, when she stops dyeing her hair.
In Sly Cooper: Thieves In Time, you get to meet several of Sly's ancestors. Many of them appear to be nearly Palette Swaps of Sly, with slight modifications to clothing or hairstyle as the time period demands. However, most jarring is Caveman Cooper, dubbed "Bob" by the others: while he's noticeably larger and more Neanderthal-like, Bentley says that his biometrics (fur length, facial features, tail volume...) prove he's Sly's ancestor. Apparently Cooper DNA is so strong it can withstand thousands of generations and still come out with a strong family resemblance.
In Find Mii of Street Pass Mii Plaza, the king of the land is represented by your own Mii. In Find Mii 2, we are introduced to the prince and princess... also represented by your own Mii, with different hairstyles. Even lampshaded at the start of the game.
If your Mii has a beard, this becomes hilarious.
Star Fox: Fox McCloud looks a lot like his father James. James (At least in Star Fox 64 before they got lazy) had darker fur and a slightly narrower head, but other than that... They dress the same too, save for Fox eschewing his father's trademark of wearing sunglasses. On those occasions when Fox does don shades... Yeah.
This appears to be the case with the Goth family in The Sims 2. If you change Cassandra's hairstyle and get rid of her glasses, she ends up baring a striking resemblance to her Missing Mom, Bella, whereas, her little brother, Alexander looks a lot like their dad, Mortimer, especially after he becomes a teenager.
The Ace Attorney series has Kristoph and Klavier Gavin, brothers who are eight years apart but look almost identical.
Also done in a much subtler, but very interesting way with the von Karmas and Edgeworth. Franziska and Miles don't resemble Manfred physically (and the 2nd shouldn't, being adopted), but if you look at each of the three character's animations and mannerisms, they are varients of all of Manfred's tics. The more noticable ones are the Finger Wag, the clentching of the sleeve, the fist-pound on the desk, and the bow/curtsy.
In Gunnerkrigg Court, Antimony is nearly identical to her mother, Surma; apparently the only traits she inherited from her father are her small nose and straight hair. This is potentially plot-relevant, as Kat doesn't have a Strong Family Resemblance to either of her parents.
Kat does resemble her parents, especially her mother when her hair gets longer. It's just normally cut too short for the curls to show.
It is indeed plot-relevant: Antimony and her mother are descended from fire spirits, whose very life essence is passed down from one generation to the next.
In Platinum Grit, siblings Kate and Andre Provocski have faces that are drawn almost identically. Several members of the MacConnor family share a recognisable "blonde and bland" look. And the lead character Jeremy MacConnor looks so uncannily like his uncle that it just has to be relevant.
In The Order of the Stick, General Tarquin, the father of the identical twins Nale and Elan, is drawn as looking the same as his sons except with white hair (brown in flashbacks), and other characters note that he looks much like Elan and Nale.
In General Protection Fault, Nick looks like almost exactly his father, but doesn't have a mustache and his hair is not yet gray.
Kell and Sheila are cousins, but look enough like each other that they can pass themselves off as each other well enough to fool their own families.
After John creates the paradox clone babies of the kids and their "parents", it's pretty easy to see how similar everyone looks, especially between John/Grandpa and Jade/Nanna. Similarly, in the flashbacks to Grandpa and Nanna as thirteen-year-olds in 1923, again they look near-identical to modern-day John and Jade, the only real difference being Nanna's hair compared to Jade's.
Becquerel was created partially using Halley's DNA, and so looks almost exactly like Halley except without a visible face.
According to Word of God, had all twelve trolls successfully grown to adulthood, they would have looked identical to their Famous Ancestors; conversely, when we see the Handmaid as a six-sweep-old, she is literally identical to her descendant Aradia save for her attire. This was pretty much the entire point: Word of God goes that the ancestors were pretty much a look at what the trolls would be like in most respects had they grown up, though admittedly that's overlooking some glaring differences on their part.
The baby guardians in the ectobiology lab already bore a strong resemblance to the four kids, but in Act 6, sprite-mode Jake and Jane bear an exceptionally strong resemblance to John and Jade respectively, with only minor outfit differences distinguishing them, and Lalonde looks just like Rose except for her shirt and her Mom-style hair curl.
The animated online epic Broken Saints: Take a look at Gabriel Dunn. Now take a look at the young man from the West in Chapter 14 Act 1.
Played for laughs in Chad Vader, where at least two characters have relatives also played by their actors. The first was Champion J. Pepper, who is a lot more loveable (if a bit crazy) than his son Clint (who I might point out was the Big Bad of the first season). Lampshaded later when Chad encounters Weird Jimmy's brother Johnny and mistakes him for the former. Weird Jimmy's ghost then possesses Johnny, essentially bringing the character back to life.
In Dexter's Laboratory, Dexter and Dee Dee are an interesting variant where they each visibly inherited different traits from their parents. Dee Dee has blonde hair like their father while Dexter inherited his mother's red hair and his father's ExpressiveNerd Glasses.
One scene took things a step further and showed where they each inherited their personalities from. The mother was shown tirelessly whipping up recipes in the kitchen with meticulous scientific precision before the father burst into the scene and started wrecking things like an idiot.
Dexter's grandfather is another, less frequently seen character, who is nearly identical to Dexter in everyway, except being old and pruning. In fact Dexter's grandfather is exactly the same as old Dexter from previous episodes.
Lampshaded: While Dexter was old, everyone kept calling him "grandpa" for obvious reasons.
Steve Barkin's father Franklin from Kim Possible turns out to have the exact same look and personality as his son.
Also, when Azula is shown not wearing makeup, she bears a pretty strong resemblance to her mother, Princess Ursa.
Hakoda's design is also very strongly based on that of his son, Sokka. It's also shown that the resemblance is more than physical - Hakoda is also The Strategist, shown to also be a capable inventor, and even has the same sense of humor as Sokka (to Bato's chagrin). Made more explicit in The Legend Of Korra, where a flashback to Sokka's adulthood showed him looking just like his father with a different hairstyle.
Also in The Legend of Korra, Aang's granddaughter Jinora bears a strong resemblance to him as a child despite being a girl. This is most notable in the season finale of Book 3, in which Jinora gets her head shaved in order to get her airbending master tattoos, at which point she's almost the spitting image of her grandfather.
When Milhouse's parents were introduced, they both looked very much like him, meaning that they also rather improbably looked very much like each other. This has led to some pretty uncomfortable questions from fans. (And Bart, in one episode). Considering that the "Lemon of Troy" episode revealed that Mrs. Van Houten is from Shelbyville, and that the Springfield/Shelbyville rivalry came about because Shelbyvillains wanted to marry their cousins... yeah. It sinks into Uncanny Family Resemblance territory with the introduction of at least one of Milhouse's grandfathers and his two grandmothers in different episodes, who of course look all the same. By the way, one of the grannies is Italian and the other (most likely) Dutch. Milhouse himself lampshades his parents' resemblance in a later episode where he casually admits that he thinks they might be brother and sister.
The episode "The Blue and the Gray" reveals Lenny and Carl date each other's sisters every Valentine's Day. Each pair of siblings, of course, look alike.
Grandma Bouvier is basically an aged-up version of Marge, right down (up?) to the improbably high beehive.
Abe Simpson looked very similar to his son Homer in his youth, though he lost his hair later in life. At one point Bart used a vacuum on Abe's face and was startled to see that Abe looked exactly like Homer without his wrinkles.
Superman as an adult in Superman: The Animated Series looks exactly like his father Jor-El did when Krypton was destroyed. When an aged Superman appeared in Batman Beyond, they even gave Superman Jor-El's voice actor to take it from simple resemblance to carbon copy.
Batman Beyond has two of these: first, Terry's younger brother Matt looks almost identical to him, something the show's creators actually joke about on the DVD commentary (the lack of resemblance to either of their parents is best not delved into here, considering the later explanation is supposedly something of an Ascended FanonRetcon). Second, when Big Bad Derek Powers' adult son appears at the end of the first season, the facial resemblance is strong enough it's pretty clear that they're family even before dialogue actually states it.
In the cartoon Back to the Future one of Doc Brown's kids — specifically, Verne — was able to pass himself off as Doc Brown's younger self during a trip to the past (his eye color even changes from his usual blue to Doc's brown). Ironically, a different, earlier episode had his sibling Jules claiming Verne had to be adopted because he bore no resemblance to the rest of the family (Jules, it should be noted, sort of resembles his mother Clara).
An Alternate Timeline of Ben 10 had the main character fully grown in a now futurized Earth having a son named Kenny, who looks like a carbon copy of his 10 year old self. In addition, Ben's Evil Counterpart also has a son named Devlin Levin who looks like his younger self before the mutations with no mention as to whom he conceived him from.
Storm Hawks: Aerrow looks exactly like a young Lightning Strike, but with a different hairstyle. That is pretty much the only difference.
They also have different eye colors. Aerrow's are green, Lightning Strike's are brown. But yeah, that's pretty much it.
Averted to an extent on Daria. Quinn and Daria have appearances unique from each other and their parents, though Daria looks uncannily like her Aunt Amy.
Daphne's parents look like older versions of Daphne and Fred.
Shaggy looks like both of his parents, and vice-versa.
Fred, on the other hand, looks nothing like his father. Which is one of the first hints that he isn't his real father.
In Phineas and Ferb, Stacy's female relatives in Tokyo all look like clones of her. Her little sister, Ginger, also looks almost like her.
Additionally, every male on Ferb's side of the family, parents, grandparents, uncles, cousins, etc., all have the same tall, thin face and squarish nose. Ferb and his Grandfather are pretty near Identical.
In Gargoyles, Angela his a near-dead ringer to Demona and has a spot-on match to Goliath's skin and hair color, and Elisa notices it immediately.
Let's not forget Elisa, her siblings,and Alex, the son of Xanatos and Fox . Elisa resembles her dad, her brother looks like their mother, and the their sister resembles both of their parents. Adult Alex looks like David with Fox's bright red hair. (Of course, he was All Just a Dream anyway, so who knows if he will actually look like that?)
In Totally Spies!, the girls' mothers looked more and more like them with each appearance.
In Recess, T.J. looks like his mom, Gus resembles a younger less rugged version of his dad and he also has a presumably great grandfather who looked just like him as a kid, Vince looks like his dad, Mikey looks like his mom, and Gretchen resembles both of her parents.
As revealed in the show Jungle Cubs, Hathi Jr., the baby elephant from Disney's The Jungle Book, actually looks exactly like his mother Winifred when she was still a calf.
Colonel Hathi (Hathi Jr.'s father) from the same series for some reason looks exactly like his father-in-law (Winifred's father).
In the episode of Family Guy where Peter Griffin accidentally kills his (fake) father and discovers that his real father is from Ireland, it's revealed that Peter looks exactly like his real father right down to the fact that they both wear a small pair of glasses that are the same width as their eyes, a white shirt, and green pants, are both fat and are idiots, but Peter lacks his father's beard.
Mort, Muriel, and Neil Goldman all resemble one another.
Chum Chum from Fanboy and Chum Chum has a female cousin Muck Muck, who looks exactly like him, except with pigtails, eyelashes and a different outfit.
The original My Little Pony "Baby" characters looked exactly like their mothers, except for less markings on their hide.
Twilight Sparkle in My Little Pony: Friendship Is Magic resembles her mom to a T. In a slightly less exceptional case, Pumpkin Cake has the exact same colors as her father, while Rainbow Dash's mane and tail are practically identical to her father. "Magic Duel" shows that, with a little dye and mane-styling, Sweetie Belle looks almost exactly like her big sister Rarity back when she was Sweetie's age.
In one episode of Courage the Cowardly Dog we see a photo of Eustace's father. Turns out he's Eustace with a snowy-white beard, however Eustace sees no resemblance. Eustace's mother also looks almost exactly like him, including being bald as well, though she wears a wig and is much shorter.
Aside from some differences in their faces and head shapes, Max and PJ on Goof Troop look like miniature versions of their fathers. Their personalities are completely different, however. This was lampshadedmany times in "Meanwhile, Back at the Ramp," much to Max's chagrin.
During a flashback in Sym-Bionic Titan, we see Ilana standing next to a woman who looks alot like her, assumed to be her mother, although this has not been confirmed.
The Secret Saturdays: According to the flashback in "Van Rook's Apprentice", Drew and Doyle look almost exactly the same as, respectively, their mother and father. Drew comments on Doyle's resemblance to her father the first time she sees his unmasked face.
Regular Show: Don's brother has the same head/facial design as him, but has the body the size of a human. Margaret's mother is revealed to look a like her, also being a red robin. Oh so averted with her father though.
Penny Proud from The Proud Family has been told that she resembles her mother Trudy with her looks.
Tim Buckley and his son Jeff Buckley looked very similar, the main difference being that Jeff's hair was straighter than Tim's. They resemble each other so much that comparisons are always made between them, even though their music was vastly different.