Tsundere/Western Animation

Usually tsuntsun ("Type A")

Kira Tonbo from Angelicate Avenue is completely and totally tsun-tsun to Kimi, then when spoken to by Koja, reverts to dere-dere mode.
Kiina in Bionicle:The Legend Reborn.
If you look at it from another point of view, then Wally from Kids Next Door is a male tsundere. He's the kind of kid who's crazy for action, but when Kuki's being sweet to him, he can't look at Kuki straight in the eye.
Helga Pataki in Hey Arnold! goes all dere-dere on Arnold in private and even has a shrine devoted to him, yet she can only act tsun-tsun and bully him in public. In fact, she could easily out-tsundere even the most extreme Anime tsunderes.
- Rhonda could easily be seen as this for Harold, especially in "Operation Ruthless" and "An Egg Story".
- It's revealed that Arnold's grandma was this when she was young.
Britanny Miller from Alvin and The Chipmunks, towards Alvin Seville (and VICE VERSA).
Gwen Tennyson in Ben 10, mostly toward Ben.
Linka from Captain Planet. No, she doesn't like Wheeler that way or so she says, but she's been close to kissing him several times and is his Clingy Jealous Girl whenever a female expresses interest in him, so...
- Actually she did kiss him right on the lips in the episode where he helped her saved her home town.

Wheeler: "Love your accent. You Russian?"
Linka: "Soviet!"

Cindy Vortex from The Adventures of Jimmy Neutron. She's far more "tsun" than "dere," but there are a few times she lets her true feelings for Jimmy slip through.
Gwen from Total Drama Island. She starts out acting Tsun, takes awhile to warm up to people, but in the end she agrees to go out with Trent. By the second season they broke up. Then third season, its the same with Duncan. While he is one himself. Dere to her, tsun to everyone else.
- Courtney also is a good example, although she can be somewhat nice, henceforth why she's also listed in Type B. She instantly takes a loathing for Duncan, yet she ends up falling asleep next to him in the Sucky Outdoors, and then kisses him in Basic Straining. After that, the tsundere aspect is greatly diminished after Courtney's Total Drama Action taking a level in jerkass.Then the Thundere act is compeletely dropped in World Tour'. She actually becomes more of a Yandere as an example of Derailing Love Interests so the writers can pair Duncan with Gwen.
  - Heather during World Tour is a perfect example of the Type A, going for the cold shoulder and insults towards Alejandro. She's even denying she likes him to Chef, and then stating in another (empty) confessional that he's "just so... perfect'!"
  - However, as of "African Lying Society", Heather and Alejandro are both tsundere for each other!
  - And finally, it's subverted in the last episode: Heather's tsun side is real, but it's clearly exaggerated to make way for a fake love confessional.
Murderface from Metalocalypse. Oftentimes he is rude, crude, and disrespectful to his band mates and the world around him, but occasionally becomes emotional and insecure of himself (especially in Performanceklok and Birthdayface). Creator Brendon Small describes Murderface as, "a self-hating bass player [...] thin-skinned and incredibly sensitive and just wants to be accepted constantly but can't get that because he's such a dick and pushes people away". [1]
Some fans believe that this is the hidden behavior of Trixie Tang toward Timmy Turner in The Fairly OddParents.
- In fact, in the episode Manic Mom-Day she truly behaves as a tsundere.
This was the personality given to Zelda in the animated Legend of Zelda, although usually only when dealing with Link.
Cute Monster Girl Callie Maggotbone on Ugly Americans is a chaotic type A.
- Shes working on it
Ren from The Ren and Stimpy Show is one towards his best friend and life partner Stimpy. Less so in the first episodes, where apart from Ren's occasional and usually justified insults, the vitriolic part of their relationship is barely visible. But, oddly for tsunderes, his positive/neutral attitude goes downhill as episodes pass. In Adult Party Cartoon, he turns into a Complete Monster (at least, in some episodes, where it was intended as Rule of Funny, but turned out very much Dude, Not Funny). His tsundere behaviour towards Stimpy varies between Domestic Abuse and I Shall Taunt You, with only the latter receiving any noticeable reaction. In earlier seasons, he used to have Cry Cute breakdowns fairly often, with Stimpy as his shoulder to cry on--in "Son Of Stimpy" and "The Big Shot" it's also very obviously portrayed that he cares deeply for the moronic cat, which is the "dere" side of his personality.
Vanessa Warfield from M.A.S.K. towards Brad Turner in the second season.
The Simpsons episode "Stealing First Base". Bart falls in love with Nikki, a girl in another fourth grade class. She's definitely a Type A. She goes from being upset because he stole a kiss from her, to wanting to be his girlfriend. He still can't figure her out by the end of the episode (though Bart did cry out, "I love you!" to her as she left).
- Bart actually got this a couple of times. When he ends up in Juvie, he becomes the target of a tough girl who may or may not like him. Bart is as confused by this girl as he was by Nikki, though this one is more (physically) painful.
Heloise from Jimmy Two-Shoes goes from tsun to dere when Jimmy shows up...and then to Yandere when her jealousy gets the better of her.
Megara from |Hercules is such a defining textbook example that her song from the film ("I Won't Say I'm in Love") has more or less become the official anthem of every type-A Tsundere ever. And Youtube is rife with fanmade music videos to prove it.
Lily from Kappa Mikey must have the diaphram of ten lions and threatens physical pain not just on her target of affection Mikey but on the rest of the cast as well. Only once in a full moon does she admit that Mikey's sweet.
Candace of Phineas and Ferb has some aspects of this. Most noticeable in "Split Personality", in which she's split into pure Tsun Tsun and pure Dere Dere duplicates.
Turanga Leela from Futurama is an Tsundere example. She has a love for violence and hit mostly everyone at least once, besides her love interest Fry. She is usually a Type B but Fry makes her irritated often, especially in the beginning. His stupidness, annoyingness, and immaturity brings it out of her turning her into a Type A. Leela at first didn't feel the same but as the series progressed, she fell in love with him, in part to Fry's persistence and also his consideration of her feelings.

Leela: "Look, Fry is very sweet. I love his boyish charm but hate his childishness!"

A rare male example: Kyle from Fanboy and Chum Chum qualifies. While usually dismissing the titular duo's pushy friendliness with snark, he has occasionally shown to crave their friendship in reality, most prominently in the episode "Sigmund the Sorcerer".
Think one male tsundere is rare? How about two of them put into the same environment? Buck Tuddrussel and Larry 3000 from Time Squad refer to each other with great amounts of disdain in their default tsun mood, but if placed in a proper situation, can be nice, open and protective over each other (though they are never at the same time). This is more prominent with Larry, who is not subject to Testosterone Poisoning.
Sarah from Ed, Edd & Eddy. It's hard to tell, because she's almost always in tsun-mode - occasionally going full-blown Ax Crazy - but she does have her occasional dere moments, mostly toward Jimmy.

Usually deredere ("Type B")

X-Men: Evolution: Miss Jean Grey, so much. She normally acts like a sweet and cheerful Cool Big Sis towards the younger kids, but goes cranky when Scott or Duncan are around. And there's her hidden jealousy against Rogue or Taryn...
Wanda from Fairly Oddparents, who tends to do all the Tsundere methods. A fan wrote this in a review of Fan Fiction about Cosmo and Wanda's failing relationship:
- Wanda is not an instigator. The only time she takes to lashing out at Cosmo is after he has done something to insult or offend her. That is self defense - It is NOT nagging. Wanda reminds me much of C-4 explosive. Quite stable unless you put a fire under it. Fact of the matter is (9 times out of 10), Cosmo is the match lighting her fuse.
Emily in the new Thomas the Tank Engine seasons. She's normally quite sweet until something sets her off. Usually when the trucks start giving her crap, Thomas acts like a Bratty Half-Pint, James acts like a Jerkass, Gordon like an Upper Class Twit, or if she just gets ideas above her station.
Wilma Flintstone from The Flintstones is a good example of a type B. She's all sweetness and light until her husband Fred goes from Jerk with a Heart of Gold to Jerkass. The Flintstones are probably a good example of what happens when a pair with Belligerent Sexual Tension eventually gets their act together and finally Spit It Out.
Then there's Annabelle, the angelic whippet from All Dogs Go to Heaven. "Touch that watch and you can never go back...I SAID TOUCH THAT WATCH AND YOU CAN NEVER GO BACK!"
Mitsuki from Kappa Mikey, for Mikey. She is soft, dependent, shy, and kind the point where nobody else acknowledges her and they often forget her name, but in one episode it's revealed that she used to be a secret agent before breaking into show business and can injure nearly anyone if need be.
Courtney from Total Drama Island. Generally polite if bossy, but if you get her mad, she gets bitchy and violent, especially around Duncan, as she shows her Tsun by refusing to admit she likes him.

Duncan: (with his and Courtney's fake antlers stuck together) What can I say, the girl can't keep her antlers off me.
(Courtney responds by kicking him in the groin)

Kuki aka Numbuh 3 from Kids Next Door is EXTREMELY cute and sweet... but she's very, very obstinate and prone to mood swings, especially when arguing with Wally aka Numbuh 4.
Frankie from Foster's Home for Imaginary Friends is very warm and nurturing towards the imaginary friends, but doesn't take too kindly to Mr. Herriman's pestering or Bloo's madness.
Maurecia from Wayside is a Genki Girl who is extremely friendly and liked by everyone in Wayside School. And she expresses her unrequited love for Todd by hitting him, constantly.
June from KaBlam! is usually sweet and laid-back. However, when something bad happens (like Henry giving her crap or something won't go her way), she's pretty tough.
By contrast to the obvious Type A William Murderface, Toki Wartooth is a Type B tsundere, usually being the nicest guy in the band, and treats every band member with a calm attitude... Except Skwisgaar, to whom he is specifically tsun towards. Still, it is pretty obvious that he does have a crush on him. Yes, a male tsundere having the hots for another male character.
Giggles, of Happy Tree Friends infamy. While normally one of the sweetest and most social members of the cast, she absolutely flips her shit whenever she sees someone harming the environment.
Yo from Fanboy and Chum Chum is a Genki Girl with obsessive tendencies towards the latter protagonist by default. Occasionally, especially when dealing with Fanboy, she will switch into tsun mode and become much less pleasant.
Fluttershy from the fourth generation of My Little Pony, especially in her relationship to animals. Often, she's very kind and sweet to them, acting as a Friend to All Living Things. But if the animals endanger her friends or make her feel unloved, she will flip.

"You're going to love me!!"

Miss Grotke from Recess is for 95% of the time an Adorkable sweetheart. But when provoked....BewareTheNiceOnes.
Beebe Bluff from Doug is pretty friendly, though she's a bit of a tsun-tsun around Skeeter, who it's confirmed she has a crush on.

Unsorted

Tasha in The Backyardigans might be one of those. Most of the time, she's bossy and wants everything her way, but during the "Giant Problem" episode she becomes a playful Genki Girl Giant.
Probably the only noteworthy thing about the most recent Fantastic Four animated series was that Sue went from being an extreme dere (a dere-mat, actually) to almost a Type A -- although with those three guys, it's understandable. This was probably spun off from her updated profile in the comics -- she's much more aggressive with her powers, to the point where she's now regarded as the most powerful member of the team.
Velma in Scooby Doo Mystery Inc has become this, being sweet and romantic when she's alone with Shaggy but then becoming aloof and irritated when Scooby horns in.
Zuko from Avatar: The Last Airbender is something of a prickly Jerkass most of the time, but has a soft, dorky center that he pretty much only shows around his Sugar and Ice girlfriend Mai.
Duncan from Total Drama Island is Tsun-Tsun to nearly everybody, but dere-dere to Gwen and Courtney (untill the third season where he is more Tsun-Tsun to her than anybody else.)
Abigail aka Numbuh Five from Kids Next Door is usually very laidback, but tends to be very "tsun" with the people she loves most, namely Numbuh Two/Hoagie and her older sister.
Non-romantic examples: Anne Chan is a mild Type B: Her dere-dere side is laid back and a Plucky Girl and her tsun-tsun is argumentative and competitive (especially around Tom and Alan). Henry is also a mild Type A when it comes to Stanley.
Non-romantic example (most of the time): Spinelli from Recess is (usually) dere-dere towards the other five main kids, but tsun-tsun to everyone else. Also, she's the most dere-dere with T.J., whom it's hinted she has a crush on...
Shuriken School has the main three female characters being different types:
- Okuni is a Harsh Type, taking cues from Sakura and Akane. She has an extremely short fuse mostly triggered by her comrades' stupidity, but she's a kind and reasonable girl when not upset. This is especially evident when around Eizan, whom she has a crush on yet vehemently denies it when pointed out.
- Ami is a Sweet Type, being usually nice (if vain) yet having a mean streak usually directed at Daisuke.
- Kita-sensei takes a middle ground to the above two, being a Mood Swinger who can turn from sweet to harsh at the drop of a hat.

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