Although played straight with some Pokémon, this trope is subverted in the anime, perhaps in response to the complaints that Dawn has mostly cute Pokémon — adorable Big Eater piggy Swinub evolved into a rampaging disobedient Mamoswine within the course of three episodes.
Then brought right back in with two of the main group's Pokémon in Best Wishes. Ash's Oshawott (who Ash even says is adorable), Iris's Axew, and Trip's Vanillite (although Iris disagrees).
Even Team Rocket has had cute Pokemon, especially Chimecho, Mime Jr., Cacnea, Wurmple, and Woobat.
Professor Icarus's Elgyem. It's got big eyes, it's all shy and timid, and it makes little "Ri-kuuuuuu" noises. D'awww.
Patamon is probably the Rookie that fits the most; of course, that's before he becomes the super-special-awesome Angemon.
Culumon from Digimon Tamers exemplifies this trope. It has to be among the most "awwwww" inducing critters ever seen.
Marine Angemon: Most of the supercute Digimon are at Baby and In-Training levels (the levels of actual infant Digimon, and the heroes' Sleep Mode Size.) Marine Angemon? Mega. (That is, the levels of the heroes in Super Mode, and post-midseason BigBads.) The Powers That Be sadly didn't let him out of the bag much, but he saves the day in a big way once. D-Reaper is a program that is basically an Eldritch Abomination. Its base matter, called 'chaos,' is the red gel its creations are made of and revert to when defeated. It keeps spreading no matter how many you "kill." See Fighting a Shadow; nothing actually destroys D-Reaper matter. Nothing except Marine Angemon's attack, normally used for healing. Said attack takes the form of pretty colorful bubbles, naturally.
Potato, the puppy from AIR that some people think was so named because it resembled a pile of mashed potatoes. It's disturbingly intelligent (Kano can apparently talk with it), says nothing except "Pico pico" and is mind-bendingly adorable!
Magic Knight Rayearth also features, in one episode, a stupidly-cute, injured, foxlike critter that Hikaru instantly adopts and names "Hikari" after her old dog. Turns out it's actually a demonic monster named Vigor, who deliberately played this trope in order to get the jump on them.
xxxHoLic also has Tanpopo, Himawari-chan's almost painfully adorable little bird. And Chibi Kitsune.
Daa! Daa! Daa! has Pepo, Luu's adorable, stuffed animal-like alien space pet that's a Peponian...from the Planet Pepo. Guess what it says? That's right. Pepo!
Wizz from D.N.Angel; cutest floppy-eared rabbit-like thing ever.
The Puuchus from the Excel♥Saga anime are meant as a parody of this. They're actually evil alien invaders and when you hit them they bleed purple and take on the haggard features and guttural tones of Golgo13. Domesticated Puuchus on the other hand turn into heroes from shows like Captain Harlock or Gundam. Not ugly, but definitely weird.
Chopper's half-human form is definitely an example. Even though creatures of his type (animal zoans) look like adult humans crossed with animals, Chopper ends up looking like a three-year-old cosplaying as a plushie, for reasons of Cute, and possibly because he was actually an animal that became half-human.
Botan, the baby boar. When it first appears, Tomoya and Sunohara aren't quite sure what it is, though they both agree that it's ridiculously cute. After the time-skip Botan is grown, but is still depicted as cute. Doesn't hurt to have kindergartners playing around it as if it's a living stuffed animal.
The big dango family, of course; they could be described best as small rolls of bread with Super Mushroom eyes.
Kirara◊ from InuYasha looks like a cross between a kitten and a fox kit, with adorable mews to match. At least until she transforms.
The little green alien creature that steals Sheryl's panties and which Ranka befriends from Macross Frontier. Later on, Ai-kun (the green critter) molts and becomes a stage-1 juvenile Vajra, and somehow still manages to act obnoxiously cute.
The main character of Princess Tutu is actually one of these! Ahiru's (which means 'Duck' and is named that in the dub) true form is that of a yellow duckling with big, big blue eyes. Even the resident Tall, Dark and Snarky can't resist her cuteness.
Pani Poni Dash! spoofs this with a cute but incredibly depressed bunny that's the pet of the main character.
Along the same lines, Pokota from Slayers Revolution is the a prince, bound into the bizarre but adorable shape of an alien bunny looking thing with gigantic wing-hand-ears, a cape, and a zipper up his stomach that opens on to L-space. He is, of course, Tougher Than He Looks.
In Fullmetal Alchemist, Xiao Mei, the midget panda actually stunned Scar into silence with her cuteness.
In Axis Powers Hetalia, most of the Non Human Sidekicks. Hanatamago and Pochi are some that are named, both being fluffy little dogs. China has a little panda, England has his little spirit friends and so on. There is also a recurring white bunny with gray ears seen with America, England and Japan (probably based on the author's pet rabbit). Tony the alien is also rather cute. There's also Kujimarou the bear cub (with drastic memory problems!) belonging to Canada.
Isako from Dennou Coil uses a group of virtual pets to do some of her chores. They are all extremely adorable fluffy round things, but underestimating their abilities would be a big mistake.
The Bearbees from Kyou Kara Maou. They're snuggly embodiments of love that sprinkle glitter, say 'Nogitsu!' and concider Yuuri and Wolfram to be their parents, making them Greta's siblings. They're highly endangered and their poop makes very high-quality, but very smelly, paint.
Pero Pero from Kare Kano, the dog that gets around by rolling around.
Moyashimon features one of the few successful attempts at making bacteria and mold spores cute. This especially goes for the series mascot, an anthropomorphic spore of Aspergillus oryzae.
The devolved dragon... slime... THING... Nyo-Nyo from Lilim Kiss.
The Keronians in Keroro Gunso including Keroro, Tamama, Giroro, Kululu, Dororo and every other that shows up over the course of the series. There's also pop-star alien girl Sumumo who isn't Keronian but might as well be.
Nyanko-sensei is so cute and round that he has spurred piles and piles of merchandise, from cellphone-straps to giant pillows. His outwardly-abrasive personality only makes him cuter, since we all know he's actually a big softie. Of course, everyone in-universe with the exception of Taki seems to think he is an ugly, fat cat.
Inaho in Agriculture Angel Baraki.
Pudding-chan and other dessert characters in Pudding in Love.
The manga "Happy Happy Clover" is filled with characters like this.
Chaffies. They are fluffy little bunny-like critters who are always smiling, with only 1 1/2 ear after a simultaneous lawnmower accident. Also, they like to wander off absolutely everywhere, getting themselves hidden amongst other Ridiculously Cute Critters.
One page in the Find Chaffy book has them hidden in a whole group of pandas.
In the main Marvel Universe, Tigra has recently gotten pregnant by Hank Pym ( really his Skrull double) and given birth. Her baby, William, seems to combine the best cute features of babies and kittens.
Gnutten & Gnuttarna from the Swedish comic Bobo are small white fluffy Cephalothorax creatures.
The Star Wars Bestiary informs us of the Voorpak. It is a tiny, almost spherical Pomeranian-like animal that Naboo nobility use for companionship and warmth. It is basically a cross between a Pomeranian for its size and fluff, a fuzzy spider for its hidden legs, and a Vampire Bat for its face. And it's a-freaking-dorable.◊
In the Expanded Universe are the catlike race Kushiban, who look like this◊. They're a sentient species. This particular Kushiban? Jedi Master Ikrit.
The blue, elephant-like species of Ortolans (which first appeared in Return of the Jedi) also qualifies, where they go into full-on Woobie Species when the Separatist Droids invade their homeworld in Star Wars: Clone Wars. Many, many players in Star Wars: The Old Republic couldn't find it in their hearts to perform any dark side actions against their kind on Hoth, particularly the one where Republic players are sent to their geothermal power plant (which they literally depend on for their survival) to destroy it.
The Expanded Universe also gives us gizka, cute little frogs with big eyes that are essentially the Star Wars tribbles .
Fizzgig from The Dark Crystal. Basically a Tribble crossed with a pomeranian and a shark.
Kitten Tigress is similarly adorable◊. which is a major part of Tigress's backstory: after seeing the ridiculously cute baby!Tai Lung grow into a snarling, selfish, greedy beast thanks to being doted on, Shifu forces himself not to feel the same compassion towards baby!Tigress, lest she do the same. But if you can't feel compassion and love to something so cute, what can you feel? Nothing. It's a broken, blank-eyed Shifu that trains baby!Tigress.
A whelp that found me as I stood, / That had a-followed, and could do no good. / It came and crept to me as low, / Right as it had-a me a-know, / Held down his head and joined his ears, / And laid all smoothly down his hairs.
Treecats from the Honor Harrington series. Yes, they are as deadly as they are sapient, but they are as cute as they are deadly. How else could they endear themselves to those people they haven't bonded to in order to obtain celery?
On the planet Tranquille around KM849(G-0) lives a little animal known as a "knafn." It is herbivorous and has no natural enemies and is easily approached and may be petted—-sort of a six-legged puppy with scales. Stroking it is very pleasant; it wiggles its pleasure and broadcasts euphoria in some band that humans can detect. It's worth the trip. Someday some bright boy will figure out how to record this broadcast, then some smart boy will see commercial angles—-and not long after that it will be regulated and taxed. In the meantime, I have faked that name and catalog number; it is several thousand light-years off in another direction. Selfish of me—-
Mouse of The Dresden Files started out this way. Harry acquired him by accident when he was hired to rescue a bunch of puppies and one of them crawled out of the box and hid in his car. Harry proceeds to spend the rest of the book carrying around the little gray furball in the pocket of his coat, and several characters are reduced to cooing over it due to the sheer cuteness. However, he doesn't stay tiny for long.
The adorable, burping yeast sock puppets that appear on many episodes of Good Eats. So popular are they on the show, in fact, that many fans have attempted to make their own.
Mystery Science Theater 3000 had a genetically engineered fuzzy cute thing called "Nummy Muffin Coocol Butter" that the Mads sent up to the Satellite. Mike fell under its/her spell, but he was forced to send it/her back because 1. she had a shedding problem that really rankled the Bots, and 2. Frank was missing her desperately.
Chicken puppet Chica on PBS Kids Sprout is this. One blogger compares her and the network to crack, and every other post on Sprout's Facebook page is requests for a plush Chica toy.
Many of The Muppets would count (With their big, bulgy eyes and fluffy bodies- specially if you live on Sesame Street), Bean Bunny stands out, as he's supposed to act cute so the rest of the Muppets wouldn't have to.
Carly's hair from iCarly and there's also Peter the Penguin and the Pee Wee Babies from iDate a Bad Boy, Marvin the Ostrich from the Fred episode and the poodle puppet and the possums from iGo to Japan.
The Book of Exalted Deeds has some very cute celestials: the fairylike coure eladrins and the musteval guardinals, who resemble bipedal ferrets. Hollyphants in their small form would also count.
Pseudodragons. They look like dragons, but they're the size of house cats. Small house cats. Faerie dragons are much the same, only with butterfly wings.
Wastems and Wastits from Human Occupied Landfill. Wastems are cute little creatures whose bodies are filled with a tapioca-like substance that can be used for anything from food to motor oil.note Possibly inspired by Al Capp's shmoos, as detailed in the Comics section. Wastits are cruel, psychotic, and make most grown men wet themselves in terror if they know what they're dealing with. And the worst part? If you don't have the "spot wastit" skill, you can't tell the difference between the two, even if the wastit is walking away from a bloody corpse with a skull in one hand and a bloody butterfly knife in the other.
The pipefox◊, a tiny furry magical creature with a snake-like body and the head of a fox.
The RPG Rogue Trader introduces us to the Gyrinx, a mid-sized cat that hangs around psykers. Of course, this being 40k, they serve as conduits to increase their master's already considerable psychic power and tend to explode if a Daemon takes interest in the relevant psyker.
The Sci-Fi version of Fluxx, Space Fluxx, has shout outs to several different Sci-Fi establishments, but all a little different to avoid nasty copyright infringements. They have a "Cute Fuzzy Alien" card that looks an awful lot like the ones Kirk had trouble with...
The sun fairies in the Universal Studios Japan ride Space Fantasy: The Ride.
Fuzzball in Captain EO is the hero's primary sidekick — a little fuzzy orange thing that has butterfly wings and can sit on one's shoulder. It can also play guitar and even gets the hero out of a tight spot.
The dinosaurs that also serve as mounts. In Super Bomberman 4, they start off as generic enemies early in the game until you blast them, at which point they turn into eggs. Walk over your first egg and you get to ride one, as well as gaining spike bombs. Any additional eggs you collect follow behind, Yoshi-style. Saturn Bomberman instead features different dinosaurs as general Louie replacements, also with unique abilities.
The Charaboms in general, but especially Pommy, debuting in Bomberman 64: The Second Attack! He even introduces himself to a few Mooks as "the cutest hero in the galaxy"!
If Bomberman B-Daman Bakugaiden IV qualifies, there's the B-Darons; mostly Funny Animals that don't talk, but clearly show intelligence nonetheless. And many of them are indeed adorable, to the point of young Bomberwomen getting Cuteness Proximity reactions around them right in the third episode!
See something at the start of the stage that looks innocent and adorable? It'll probably kill you on contact. They might be kid mice holding balloons at an amusement park or weird panda umbrella things, but they're still every bit as deadly as everything else.
In Final Fantasy XII, they threw in some literal Killer Rabbits by introducing some bosses in the form of the game's terribly cute Dream Hare creatures. (Imagine a tiny bunny with a giant puffball tail and feathers for ears, and that's about the gist of it.)
Fury, one of the later mini-bosses in XII, resembled an extremely fluffy purple and white rabbit.
Rabites. As the name suggests, the look a little like rabbits, but rounder and fluffier. They are usually the earliest and weakest enemies in each game, but Seiken Densetsu 3 features the Black Rabite as the ridiculously powerful Bonus Boss. Evil in its cutest form!
Flammie from the same franchise. He's a fluffy, four angel winged dragon with big eyes and ears.
Yoshi from the Super Mario series easily falls under this. Being a small dinosaur with huge but adorable eyes, a big nose, shoes, and possibly sounding cute whenever he "speaks" (saying "Yoshi!", various exclamations such as "Wow!", "Whoa!", "Yay!", "Ha!" and "Wah!", and several unintelligible noises), who's to say he's not cute? Though he does get less cute when you find out how exactly he can whip some ass in the Mario and Super Smash Bros. series.
World of Warcraft has many "Vanity Pets" (as opposed to Combat Pets used byhunters) that fall into this category, including a panda cub (which ups the ante by falling asleep), dragon whelps and baby murlocs. Okay, not many consider murlocs cute, but the baby version is so much cutie-fied (and does a funny dance) that most people don't care. In Wrath of the Lich King there is a quest where you have to rescue baby murlocs being kept locked up in cages...and when you open them, sometimes they say, "Mama?" or "Dada?" and then they follow you in a little scampering group.
The titular character of the Kirby series... along with nearly everything else in the franchise. Exceptions are the final bosses, and Meta Knight. Unless you break his mask.
Guild Wars has rollerbeetles, giant rolling beetles that make cute little chittering noises. During Canthan festivals, you even get to participate in Mario Kart-style rollerbeetle races.
Shadows from Kingdom Hearts. Big heads, big, wide eyes, and so little and huggable looking. A lot of the smaller Heartless fall into this category. They are so huggable you can almost ignore the fact that if you get within an arms' reach they will plunge whatever limbs they have inside your chest and rip your heart out.
If you have the right items, you can turn yourself into a small cute frog, rabbit, dog, etc. in Gaia Online. Cue the delight if you enter the Zomg! game as a frog. Not to mention all the fluffs in the game itself.
The main Monsters you run into in Wario Land Shake It are little banndana-waring red balls with feet and mouths known as Banditoes. They don't actualy do any damage, they just walk about and bounce off your fat gut, and grabbing them causes them to panic in a way that can cause just a little bit of empathy for them. Also, they come in multiple types - yellow, (They jump all about the stage.) Blue (They inflate and float, making a face that looks suspiciously like that anime "Hey-I'm-cute" face we all know and love (:3, to be exact) all the while.) and a lighter blue. (They have forks on their head which can actualy harm you, but cause them to get stuck to the cealing or walls when thrown, with struggling included.) It seems even the game likes them, as some missions to unlock the music soundtrack require you to get through a stage without killing a single baddie.
Nelly Cootalot has spoonbeaks from the Barony of Meeth, which are not only cute for their eponymous spoon-shaped bills, but also serve to show how evil Baron Widebeard can be when he enslaves them to work in the Saul Mines.
Nall and Ruby from Lunar, being what appear to be adorable winged cats with high-pitched voices. Until they become full-fledged dragons.
The Yordles from League of Legends count, pretty much being Moogles in all but name. Teemo in particular was the game's first designated cute champion.
Also Fizz, who is basically an amphibian Yordle.
Poros◊ which inhabit the Howling Abyss map, who are tiny white furballs with very small limbs, disproportionately large tongues and goat-like horns. They can be fed a Poro-Snax, which will cause them to happily run around in a circle◊ once and grow larger.
All of the mooks in Hello Kitty Online are even cuter than they are dangerously aggressive. As is pretty much everything else in this Sugar Bowl world.
The fluffy wamblers from Dwarf Fortress are described as, "known and beloved for their warm hearts, gentle natures, and stumble bumblings...They are widely held to be 'adorable,' and many dwarves consider them to be a delicacy." They're also respected as killers of bronze colossi.note After a famous occurrence of an adventurer (somehow) killing a colossus by throwing a wambler at it.
Remlits, little siamese cat-raccon things with big bat ears... at least, during the day. At night they're a whole different matter◊... You can make the Remlits stay ridiculously adorable all the time if you complete a certain sidequest, however.
The Kikwis, who resemble a cross between a penguin, a beaver, and a shrub. Not to mention their Verbal Tic...
Furrikin in Lusternia. Bipedal, intelligent little fuzzballs, they resemble anthropomorphic archetypical animals. Furrikin can look like anything from a panda bear to a raccoon to a sheep, but don't let their appearance fool you - they're smarter than humans and very fast. And not all of them are peaceful, either.
Teddie from Persona 4, it's like this trope page is describing him on purpose. As the name would suggest, he looks like an overly large, animate teddy bear, with short arms and legs and a huge head and eyes.
Funny enough, it is kind of describing him on purpose-Teddie looks the way he does because he wanted humans to like him.
Baby mobs in Minecraft. Just making the body smaller while leaving the head the same size should not produce such cuteness!
As of the "Pretty Scary" update, bats count as well. They're small brown flying bundles with big ears that make adorable squeaks and hang on walls by their tiny little feet. Aaaw!
The Baliflids in Ascendancy — although judging from the art, this is a case of either Ugly Cute or Informed Ability. They are so cute they can force all other species to make peace with them at once.
The Nopon in Xenoblade. Small? Check. Fluffy? Check. Adorable speech pattern? Check. This cuteness causes a stark contrast from the other more human-like sentient beings in the world, and are fully aware of it. Some Nopon use their cuteness for their advantage, while other lament that no other race takes them seriously.
Flower Fairy has the pet flower fairies the player get from harvesting selected plants.
The Mimigas from Cave Story can count. Cute little bunny/dog creatures with big ears. What's not to like?
Pikmin, of course, which utilize every last one of the tricks listed up at the top of the page. Many of the monsters would qualify as well.
Rewrite has Kotori's "dog" Chibi-Moth, who is actually a baby miniature mammoth. Since it has its tusk and trunk hidden, it ends up looking like a strange little adorable furball. Kotori insist that its a dog though, but she has good reasons to do so, despite giving him a name that basically means "little mammoth."
Fluffy in Hazard's Wake, whose cast page entry even states, "Does Fluffy have a point other than being the cute mascot-ish character?"
In a long defunct webcomic, Acid Reflux, we saw critters similar to those that now grace the image at the top of the page: Melting Pandas. They are almost Exactly What It Says on the Tin, although it's uncertain whether they truly are melting, or just completely boneless. Plus, oxygen is a powerful narcotic to them. Apparently, they only existed to be adorable. The only ones that were still alive were ones that had been put in stasis at an old museum. Upon hearing about the two main qualities of these creatures, one character commented that maybe there's a reason that they were extinct.
All of them. Even the grumpy-looking gargoyle-things, the snarly Godzilla-Expies, the giant mantids, and flame-spewing dragons. Even the mutant and evil versions of same. And they have baby forms.
Petpets, pets for your Neopets. Even cuter than the Neopets, if that's possible.
Along the same lines as Neo Pets are the Webkins. Thus far, Gantz has managed to make every species imaginable into a Squee-worthy plushie covered in their trademark stringy fur (even, oddly, animals that tend to lack fur such as frogs). The things aredesigned to make kids scream, "OMG!!! WANT!!!" after all.
CAFs — Cute Animal Friends — are the results of an author attempting cute and instead getting diabetes-inducing twee. Particularly bad examples end up as little more than big eyes, fur, and cute cooing sounds, like oversized tribbles. Some can be trained or educated into becoming productive members of the multiverse, but a particularly Small Annoying Creature may be better off simply fed to the nearest mini.
From Cartoon Hangover, who produces Bravest Warriors, we have Puppycat and the Temp Agent's turtle in Bee and Puppycat. Puppycat is a badass adorable who may object to being called cute. The turtle is a straighter example as it just sits there in the scene and is cute and funny.
Guano from Kappa Mikey. Of course, it's obvious he's a parody of Pikachu.
Halfway subverted with "Cujo", the lovable ghost pup in Danny Phantom. It's friendly and adorable in small mode, but can turn big and aggressive if it needs to. "Yikes" is a far more appropriate word for that one.
Parodied on The Fairly Oddparents with the Gigglepies, big-eyed, Carebear-esque creatures who speak entirely in rhyme. It's eventually revealed that they are actually alien conquerors who enslave worlds with their hypnotic cuteness.
Nibbler probably qualifies — he's pretty weird looking, but he's small and squeaky enough to make the tough, no-nonsense captain Leela go to pieces and adopt him as a beloved pet. He later gets a little red cape and diaper. It turns out that his entire species is sentient, and uses their cuteness as a ploy to infiltrate places where the local species is bigger and uglier as part of a giant conspiracy.
In the episode "The Problem with Popplers", the Popplers themselves, as they are actually the young of the sentient, not to mention angry Omicronians.
Katie the little... uh... fuzzy yellow thingy (she doesn't match any of the other animals) from Horton Hears a Who! The original Horton illustrations by Dr. Seuss also fits this trope.
Once The Simpsons were at a petting zoo and saw a cute little lamb with big eyes. They all let out an "Aw!", then saw an even littler lamb with even bigger eyes. They let out a bigger "AWWW!!", then saw the littlest lamb with the biggest eyes, and let out the biggest "AWWWW!!!" of all. Then the second lamb walked in front of the third one, and Homer shoved it out of the way. Video clip here.
Chuck Jones had a penchant for ridiculously cute critters that brought out protective impulses in unlikely characters - like the kitten to bulldog Marc Anthony, or the penguin to Bugs Bunny. Early in his career he did shorts which starred ridiculously cute critters, such as Sniffles the Mouse among others. It wasn't until hanging around with the likes of Tex Avery that he began to use more humor.
Ridiculously cute critters have gone in and out of style when it comes to Western Animation as a whole, having their original heyday in the 1930's with Disney's Silly Symphonies shorts and the copy-cat series of just about every other animation studio at the time. By the time World War II came around these were chucked out the window in favor of the Karmic Trickster and the Screwy Squirrel, but they resurface periodically.
Snap, Rudy's little chalk drawing in ChalkZone. Those huge eyes? Sweet nature? A bit of a daredevil? Fingerless hands? SO CUTE!
Despite being quite the trouble maker and all around annoying, Peri from Spliced (who seems to be the cross between a cuttlefish and a squirrel... or maybe a cat?... or a fox perhaps?... or maybeOH NEVER MIND), with his big eyes, huge grin, and buck teeth, seems to be a favorite among female fans.
The Penguins of Madagascar has Mort the mouse lemur and Eggy the duckling. Private probably qualifies as well - he's made even King Julien go "Awwwww". Private manages to attain a level weaponizable cuteness in one episode. Naturally, Skipper takes advantage.
Reginald the koala from American Dad!. In his first appearance, he even had a theme song and a montage dedicated to his cuteness. The fact that he's a secret agent who works for the CIA probably makes him even more adorable.
Like the Futurama example above, the Phineas and Ferb episode "Meapless in Seattle" has the alien Mitch become a being so cute that he can entrance people, including Phineas.
Two words: Baby. Perry.
Mr. Mumbles from Dan Vs.. may not be well groomed, but that kitty is adorable.
Several of the housemates in Foster's Home for Imaginary Friends come off as this, such as the one-time character Crackers, recurring background character Fluffer Nutter, the friend Wilt helps in Good Wilt Hunting, etc. . . . Berry is a subversion, World from Destination Imagination has shades of it, certain characters like Eduardo come off as this, but more of a Gentle Giant-type. Bloo's probably too much of an Attention Whore to be seen as this.
Pygmy marmosets. The smallest monkeys in the world, and very adorable.
Baby emperor penguins.
Penguins in general.
Babies, period. Given that babies of nearly all vertebrates, from mammals and birds to even snakes and sharks share a number of similar features compared to adults, like oversized heads and eyes, scientists speculated that we're as a species genetically hardwired to find such features cute.
The "sand cat◊" of Afghanistan is easily the least intimidating of the wild cats. Their heads and ears are larger by comparison to their bodies than those of house-cats, and their faces are wider, but their bodies are smaller. Even the adults look like kittens!
Baby crocodilians, in contrast to the more fearsome adults, count as this. While sharing many of the "cute" characteristics with other animals (bright, cartoony eyes, and a tiny snout that would make them look not out of place in Bambi), they can even chirp like baby birds!
By extension, baby dinosaurs as well. Many fossils of young dinosaurs have been found and they're thought to be as cute as buttons when they were alive. In fact, its been theorized that baby tyrannosaurs were covered in down.
Owls. Especially saw-whet owls◊. They've been known to make hardened ornithologists explode into rainbow confetti and little pink hearts.