The casual wear for Material-S is based off Ranpha's cheongsam from Galaxy Angel while Material-D's casual wear is copied from the first appearance of Aizawa Sakuya in Hayate the Combat Butler. The latter is a bit of an interesting case since Sakuya's overall character appearance is very similar to Yami's with the hair and eye colours and the hairstyle.
Hayate ends up facing down a Mazoku who goes by the name of "Archer", and Fate ends up facing down a Mazoku named "Mokka" during the Red arc of the story. Hayatelampshades the situation against her opponent, of course.
Lina's cell phone has "Get Along" as her ring tone.
In Revolution, Corona ends up facing a mazoku that has a resemblance to Nanaya, complete with a knife and a crazed look.
In Revolution Ixpellia gets her hands on a rebuilt Blessed Blade that absorbs the negative energy that Mazoku produce and purifies it. She then uses that to pull an attack that's similar to Excalibur.
Twilight Sparkle, Ace Attorney: The Royal Turnabout has a similar Actor Allusion to the one above, and with Rarity too. Rarity's full name is mentioned as being Rarity St. Germane. The second part of her name is her voice actress's name, with the additional horse pun.
In "Time Terror", Tim Allen voices a sheriff... again.
In "A Day at the Office", Calvin's adult pseudonym is "Ryan Segal Hanks", a mashup of Ryan Stiles (who voices Socrates), Pamela Segal (who voices Calvin), and Tom Hanks (who voices Hobbes). Apparently it "just came to him".
What's more, the prosecution's name is "Tom Adlon Stiles"!
An interesting example is Dirty Little Secret which plays with the fact that George Newbern is the voice for Superman and Sephiroth by making Superman the In-Universe English voice-actor for Sephiroth due to a rescue in Japan, including Superman actually cosplaying as the General at the Metropolis movie premiere and fighting a group of villains with an improvised Masamune, which freaks the villains out! This quickly becomes memetic among the rest of the League and causes Superman no end of grief, with the effects of it actually extends into the time of Batman Beyond. Jonn prophetically points out at one point that Supes will Never Live It Down.
During the arc of You Got HaruhiRolled! which parodied Persona 4, all of the character's Personas were anime characters who shared voice actors with them.
In the Captain America/Young Justice crossover And Superboy Makes Three, Tony Stark references how Steve Rogers looks a bit like Johnny Storm. Chris Evans played both Johnny Storm in the Fantastic Four films and Captain America in the Marvel Cinematic Universe.
In the MST for The Horribly Bloody Death of Kairi in A Random MST, the characters comment on Kairi and regeneration. Kairi's voice actress also played Claire on Heroes, who also has regenerative powers.
In Club Pretty Cure by the same author, Ryan is known for two things (aside from wearing her sister's old ballet uniform to her own gymnastics meets and being rather Spoiled Sweet): driving a Ford Anglia around the back of Montana Manor and reciting poetry while drunk on the wrong kind of vodka. She also once yelled at Susana during a tense moment at the Battle of the Bands, "Are you a drummer or not!?" As for Susana herself, she once responded to Padme asking how she knew Lars Ulrich was once a tennis player before joining Metallica by remarking, "I read all about it in Metállica: Una Historia."
The Japanese versions instead has Ran make one to Saeko Chiba: "Maya never tripped... like that."
One occurs when Hiroshi, after clumsily dodging a laser from Kuro in episode 2, is met with this question from the latter: "Training for the ballet, pink-o?" In another movie, one of Rupert Grint's co-stars plays a character who gets accused of doing the same thing after dodging a rogue ball during a sports match.
There's another one in episode 30, when the Cures encounter a basilisk after several girls get petrified.
In the Kanon AU Canon In G, the female Kuze now has a first name: Hiroka. Aside from being an actual name that somebody would give their kid, it's also a contraction of Kamiya Hiroshi, Kuze's voice actor from Kanon 2002.
In the Sliders fanfic Refugees, Natalie Nassau was described by Colin as looking "like that girl who did Noxzema commercials." Guess who that was, and what role she played in Sliders?
Draco: (in response to attempted Occlumency by Snape) I fobbed him off with the abbreviated presentation of What I Did on My Holidays, and now he's sure at least one of us is mad. Snape: (after viewing said memories, in which a girl sings "All I Want for Christmas is You") Perhaps I should have checked the expiration date on that bottle. Any drink which makes me hallucinate about attending concerts with Sibyll Trelawney cannot be good for me.
In the Harry Potter fanfic George Weasley And The Computational Error, George takes up the psuedonym "James Oliver." James and Oliver happen to be the names of the actors who played Fred and George in the films. When Remus goes back in time, he takes the name Thewlis, which is his film actor's last name.
Deanna Troi (played by Demona's voice actor Marina Sirtis) is in the Top 10 Non-Human Babes list.
While Angela thinks Wayne and Garth's Top 10 list is just silly, she continues to watch the show from Elisa's place because David Duchovny (Who, along with Brigitte Bako, was on Showtime's Red Shoe Diaries) is hosting.
Similar to the above example, Raven finds herself in Twilight's body in My Little Titan.
In the Firefly fic Name, Inara's parents' names, Monren and Veta Serra, are taken from actress Morena Baccarin's first name and her mother's name, Vera Setta. When there was no WOG on official birthdates, the author used the actors' birthdates for reference.
Chapter 66 has a gag about Inu-Yasha and Ranma having the same voice. The gag is also done involving Rainbow and Applejack, whom also share a VA.
There's also a gag in the second chapter where the ponies remark that Shampoo sounds similar to either Spike or the mayor, whose VA likewise voiced the three characters in their respective series.
Another gag is made involving when Ranma-chan puts on Lina Inverse's outfit. Both were voiced by the same seiyuu. The gag returns in chapter 80, and Asuza ends up as Sonoko from Detective Conan; again, this trope is in play.
And of course, the inevitable DisQord gag is made, with him taking on John de Lancie's appearance, and getting mobbed by Star Trek fans.
The first thing Five says to Four is "So you've decided to join us this time, have you?" Tom Baker, of course, has consistently refused to reprise his role as the Fourth Doctor in any of the multi-Doctor episodes (unless you count "Dimensions in Time", and even then he just spoke some lines into a microphone).
At one point, Seven mentions he thinks it would be better if they all worked on solving the mystery alone, as "too many bakers spoil a crust". Four looks vaguely alarmed, and Six demands to know what he's talking about.
Three and Six depart for Gallifrey together, and Six mentions that saving the planet from themselves would be "the ultimate adventure, you might say." Both Jon Pertwee and Colin Baker played their respective incarnations of the Doctor in the 1989 stage play The Ultimate Adventure.
Peri asks Six if he and Maxil are related, and Six scoffs at this notion. Of course, both characters were played by the same actor. Six later asks "Could you picture me as a stranger, Miss Brown?" in reference to BBV's video series The Stranger, in which Colin Baker and Nicola Bryant played the Stranger and Miss Brown.
Six tells Four "It's a wonder I got more than seven years out of you."
Most of the Doctors bicker, but Two and Three are definitely the worst. (Patrick Troughton and Jon Pertwee enjoyed pretending to hate each other at fan conventions.)
Ten calls Four an "arrogant overbearing smartass" during their goodbyes, probably referring to the end of Tom Baker's tenure when he became incredibly difficult to work with on-set.
Ten is especially glad to see Five, referencing how David Tennant became an actor entirely in the hopes that he might get to play the Doctor, after his adoration of Five's episodes in his childhood. Keep in mind that The Ten Doctors was written well before "Time Crash".
However, the end was uploaded after "Time Crash", and in said end Ten says he hopes to see Five again, and Five responds with this gem...
You'd be hard pressed to find a RWBY fanfic that doesn't have Yang drop a pun somewhere in it. Barbara Dunkelman, Yang's voice actress, is notorious for constantly coming up with puns for absolutely anything and everything.
Multiple people have commented that Lelouch and Ichigo sound very similar, including themselves.
As an alias to get her and Ichigo through Seireitei, Kukaku calls Ichigo KoizumiNero.
Lelouch also notes the similarity to the voices of Rukia and Euphemia. Though he doesn't use Euphy's name. Strangely enough, it's very coincidental that in chapter 59 that Rukia did a small voice cameo as Yoko for Ichigo and Shinji's special reenactment of their favorite series.
An in-universe example. After role-playing asKaminafor a school project Ichigo winds up later spouting lines from the character throughout the series including Kamina's "believe in the you that believes in yourself" speech to Kenpachi of all people.
Harry Osborn's physical description is more in line with his movie version. IE: he looks like James Franco.
It is revealed that Mary Jane has gotten the part of Marie Antoinette. Kirsten Dunst played both Marie Antoinette and Mary Jane, and indeed, when Mary Jane expresses nervousness about whether or not she can handle the role, Liz Allan reassures her:
Liz Allan: If Kirsten Dunst could pull it off, I'm sure you can
Obadiah Stane's voice is described as having "an uncanny resemblance to that of Jeff Bridges". His physical description also matches his appearance in the Iron Man movie, where he was played by Jeff Bridges.
A subversion occurs in Ultimate Spider Woman when Mary Jane is reading a magazine and reads an article that claims that Kirsten Dunst would be the best choice to play Spider-Woman. Mary Jane is extremely offended, since Dunst doesn't even look anything like her.
During a conversation with Dutch in the Halo/Mass Effect crossover When There Was A Tomorrow, Tali pauses before noting he "reminds her of someone." Most likely she's referring to Kal'Reegar, since both Kal and Dutch are voiced by Adam Baldwin.
One chapter of the Stargate/X-COM crossover XSGCOM has Heimdall taking the place of Janet Frasier, both of whom have the same (voice) actress.
The premise of the Young Justice fanfic Bird Song is that Robin has a natural talent for singing - so natural he doesn't notice when he starts. His voice actor is none other than singer Jesse Mc Cartney.
In the Merlin fanfic The Student Prince, the romance between Uther and Igraine began when the latter came to the former's room to ask for some coffee. Anthony Head played Uther in the show, and he also appeared in a series of Nescafe ads, playing a man who flirts with a neighbour over coffee.
In the Ask Fluffle Puff short "Horse M.D." (which parodies House M.D., in case you didn't guess), you might wonder at first why there is a pony wearing a costume out of TRON: Legacy, until you realize it's a ponified Quorra, who share the same actress as Dr. Remy "Thirteen" Hadley, Olivia Wilde.
Weiss Reacts: Tohru is mentioned to sound similar to Akali and Leite. Her debut chapter also involves her being mistaken for Minako. Yang also ships her with Minako, too. All of the above characters are voiced by Laura Bailey.
Later, Minako cosplays as Nodoka Manabe. She even mentions feeling as if this wasn't the first time she wore the costume, either...