Mindy of Drake & Josh in her second appearance only. The animosity she had towards Josh in her first appearance had more of a Magnificent Bastard vibe then Tsundere, but her second appearance they realized they were evoking Slap-Slap-Kiss. After that she was a rather loving girlfriend.
Evelyn Kwong. Cookie didn't realize what he unleashed when he said that the challenge of beating him was what motivated her.
Moze also qualifies, to a lesser extent. Outwardly, she's snarky and aggressive, and she only really shows her deredere side to Ned, and sometimes Cookie.
Murphy Brown. Murphy is, of course, usually incredily cranky and prone to violence, but exhibits some tsundere tendencies with all three of her main love. Minterests:
With Jake Lowenstein, she insists that she "becomes a different person" when she's.with him, and they fight constantly.
Both she and FYI's sworn enemy Jerry Gold quickly made it apparent that they loathed one another. Eventually (and to their initial horror), they realized that they did indeed have feelings for each other. (Jerry could also be considered one of the rare examples of a male tsundere.)
When she first meets Peter Hunt, she actually goes so far as to punch him in the face seconds before show time. They bicker, call each other names and play pranks on each other until a later episode in which Corky suggests that Murphy has some interest in him. She's absolutely appalled at the thought, but a few episodes and one more fight later, they're both making out in her office.
Jessica Devlin of Shark liked to combine the cold shoulder with the smirk, especially in her dealings with longtime rival Sebastian Stark.
Lois of Malcolm in the Middle. She may constantly scream at and berate her sons, but it's also apparent that she loves them all deeply and only wants what's best for them. She is more Sweet with her husband, Hal: in general if they're alone together she's a melty pile of deredere, but he can set her off just as well as the boys can: he just doesn't do it as frequently.
Jackie Burkhart of That '70s Show is a classic Harsh Tsundere during the early seasons, when she was dating Kelso. She's naturally bossy and likes to feel in control of the relationship, whereas Kelso likes "doing it", making him easily exploitable, and him being Too Dumb to Live doesn't help much. She mellows out once she starts dating Hyde after Kelso flees to California to avoid getting married to her.
Maggie from Sliders. Leans tsun in season 3 (to contrast with Wade), dere in season 4 (to replace Wade), and reaches equilibrium in season 5.
Perry Cox in Scrubs is a very rare example of being both a guy and and very old compared to other examples of this trope. His tsun side is mostly directed towards JD, whom he constantly berates for his childish or effeminate behavior, but is secretly proud of his commitment to medicine and caring for his patients as actual people.
"OI! WATCH IT, SPACEMAN!" Donna Noble of Doctor Who is an over-the-top tsun type in her first appearance and is her default mood (though toned down to levels that allowed for more well-rounded characterization when she became a regular) but she can be dere. Also a Fiery Redhead.
Sam Puckett of iCarly. Very Harsh, especially towards Freddie. Only Carly can usually bring out her "dere" side. Although later, Freddie is able to bring out her dere side also. She didn't accept this very readily.
Sherlock Holmes from Sherlock is almost always a sarcastic, rude, Insufferable Genius... Except with John and Mrs. Hudson — and that, too, only when he's feeling particularly charitable, or when they've done something incredibly loyal.
Quinn on Glee usually gives the cold shoulder to Puck; however, there have been several times when she has opened up to him. She also has a short temper with her boyfriend Finn but given that he's The Ditz, he kind of needs someone to boss him around. Most obviously would be the relationship Quinn has with Rachel.
Sue Sylvester is in tsun mode nearly all the time, except during her brief relationship with Rod in "Mash-Up" and with her disabled sister in "Wheels."
Lauren, who's also often in tsun mode, but When She Smiles there are hints that she really likes Puck. Her song I Know What Boys Like spells it out.
Monica: I'm Rachel. I love Ross! I hate Ross! I love Ross! I hate Ross!
Kelly from Misfits, who is violently aggressive and very easily provoked - she's forced to do community service for attacking a girl who insulted her, so that should tell you something - but uses her temper to hide her deep insecurities, and is a genuinely kind and sensitive person underneath it all. Oddly enough, both sides of her personality are emphasised by her strange flirtation with Nathan - she does try to be nice to him and helps him out when he's in trouble, but he can be such a snarky littlebrat that she typically ends up punching, kicking, slapping or otherwise mauling him at least three times per episode. Ironically, he later confesses that he likes her attitude problem and the fact that she's the only person who slaps him when he's being a jerk.
Major Kira Nerys of Star Trek: Deep Space Nine, a fierce, fiery former resistance leader and Number Two in the station's chain of command, who just happens to melt into a cuddly pile of smiles and tenderness when she and Odo are alone post-"His Way." And frequently before, with her various earlier love interests, although not to the degree seen in Season 7.
Odo himself is a bit of a tsundere. His first appearance had him berate Commander Sisko for carrying a phaser on the promenade immediately after he used said phaser to subdue a violent criminal. His law enforcement ranges from zealous to fascist. He's openly contemptuous of Starfleet. Pair him with Kira or Lwaxana Troi, and he becomes a pussycat.
It was revealed in the Deep Space Nine episode "Destiny" that Tsundere behaviour is part of the Cardassian mating ritual.
Benny from The George Lopez Show is a tsundere mom. She's usually rude and belligerent towards George, but there's been more than one episode dedicated to the fact that she really does love her son.
Miley from Hannah Montana is Harsh to Jake Ryan when they first meet. Eventually, they enter a relationship, but then break up. When they later meet as friends, she acts Sweet.
Wakana from Kamen Rider Double starts out this way. While she may appear to be a Bitch in Sheep's Clothing, she seems to genuinely like being Wakana Healing Princess on the radio and Philip brings out her softer side. Then she has a Heel-Face Turn and her switch gets stuck on Tsun until the very end of the show.
Kamen Rider OOO also has deserves a mention and it appears that it is an angry bird named Ankh. He is usually a tsun on Eiji, but he actually cares for him in the end.
Tasha Mack from The Game. A large part of her tsuntsun personality comes from her younger days as a single mother surviving on her own, so being fierce was her defense. Although this works when she is going up against people she doesn't intend to have a relationship with, it sort of backfires when she wants to pursue a relationship.
Tasha: Oh my god! You're breaking up with me?! I will kill you! Please don't leave me, cause I will kill you!
Holly J Sinclair's default mode is Tsuntsun, she acts catty and tough and in charge... unless she's alone with someone, and her Deredere side shines through to actually level with someone. It has taken seasons of character development to get over this... somewhat, she still defaults with snark and sarcasm and calls herself on it.
Bianca similarly has a rough Bad Girl Tsun side, casually insulting to anyone and everyone. However after the ending of Season 10 she's let her Dere side show up when she's with Drew, Adam, and Imogen. The rest of the cast still has to deal with her Tsun side exclusively though.
Kate Beckett from Castle is a tsundere towards Richard Castle. Harsh (tsun tsun); she's harsh and abrasive to many but has a softer side that only Castle can bring out. When he shows interest in other women she becomes intensely jealous yet refuses to admit it.
Rikki Chadwick from H2O: Just Add Water. Her Tsuntsun side comes from living with her poor father and seemingly being a loner most of her life. It doesn't help that the boy she is deredere for is unknowingly trying to expose her secret. She even remains the same after she's properly gotten together with him though her deredere side comes out a bit more.
Arthur Pendragon from Merlin is like this in his friendship with Merlin. He'll snark at and insult Merlin to no end, but when the going gets tough, or it's just a serious moment, he's not afraid to tell Merlin how good a friend he is.
Clare Edwards of Degrassi is a sweet gentle kind girl with little hints of snark to her name when someone does something a bit dumb... unless she finds a boy she likes. As her initial reaction to all three boys she's dated was to become instantly annoyed at everything they did or said for at least an episode or three. With K.C. this lasted most of Season 8. She also shifts to her Tsuntsun nature when betrayed or alone, so it's not strictly a romantic play. It's her defense against getting hurt.
Inara Serra of Firefly is a registered Companion with extensive training in social interactions, keeping her cool, and saying just the right things to make people happy. Her job suits her: she is polite and genuinely kind to everyone, unless otherwise warranted, to the point where she can get along with people from all walks of life but feels like she doesn't really fit in anywhere. Then she rents a shuttle from Captain Malcolm Reynolds. Cue back and forth between admiration and Volleying Insults.
Ted from How I Met Your Mother is a bit of this: his various virtues, especially his Up to Eleven level of dedication and compassion towards his friends, are very impressive, but he's also prone to impulsiveness and irrationality, combined with very strong emotions, which often results in him doing jerkish things before his brain kicks in and he realizes how he's acting, which he inevitably repents bitterly.
Dr. James Wilson from House is a caring, polite, friendly to all living things Deredere oncologist... except where his best friend Dr. Greg House is involved, and suddenly he can Tsun it up like the best of them.
Downplayed by Farscape in the character of Aeryn Sun. She might seem to be a Tsundere at first, but is disqualified for running hot and cold at the same time, as opposed to running hot and cold alternately, resulting in a sort of permanent The Spock exterior with passions that never quite surface; a definite lack of Slap-Slap-Kiss due to her Megaton Punch hurting Crichto and her coming by her behavior honestly as a borderline Super Soldier trained The Spartan Way suddenly cut adrift from her in no wayMildly Military lifestyle and ending up on the wrong end of a Stern Chase. ...ta-daa.
Jeff Winger from Community with regards to Annie Edison. He may have started out lusting after Britta, but now he alternates between realizations that he cares about/loves Annie, and loudly denying any sort of feelings or attraction to her face.
As does Susan from Coupling to some extent. If she uses the word "apparently", run.
This Monty Python sketch is a tsundere butcher with a boater hat.
Lynda Day from Press Gang embodies this trope par excellence. "Lynda's favourite colour is obedience, folks. It's true! Hard? They had to use an industrial laser to pierce her ears!" "Her ears aren't pierced." "I didn't say it worked!"
B'Elanna Torres from Star Trek: Voyager is a unique example — her tsun and dere halves are different species. Since she's not especially proud of her Klingon side, she tries to live more as a human; she's a good officer and a caring friend, and even has some "girly" habits like reading romance novels. But when B'Elanna gets mad, she gets MAD. Tom Paris has the bruises to prove it.
Lana from Frasier definitely deserves mention here. For a while, she is sweet and friendly, but tick her off and her volume goes straight to 11.
Being Human's Nina Pickering is sarcastic with everyone, but has her sweet moments with George.
Rachel Berry of Glee is a perfect example of a tsundere who is neither Harsh nor Sweet - or, rather, she goes back and forth between the two.
Maybe not a strong example, but Calleigh Duquesne seems to act tsundere towards Eric Delko sometimes in CSI: Miami.
Fiona from Burn Notice. When Michael tells her in one episode to disable the Criminal of the Week's car, she attaches a blasting cap to the gasoline tank. Sure, it disables it, but it nearly kills their mark. She truly cares for Michael though, and she loves hitting people, as seen in the very same episode, where she uses not one, but 3 Armor-Piercing Slap on Sam in order to make a getaway.
Her relationship with Mike did slowly head down the dere road during season three, but the conflict regarding Jesse is bringing the tsun back again. Maddie also sums up their relationship perfectly while firmly sinking the Jesse/Fi ship.
Maddie: They love each other. And they hate each other. But it's always each other.
Lois Lane of Smallville. She starts out on the Tsuntsun side and slowly shifts toward Deredere. Other characters on the show seem to have Tsundere tendencies also, including most of the female characters (even Martha Kent, toward Lionel Luthor), but also Lex Luthor, who seems to alternate between a man-crush on Clark and spitting venom at him.
Athena from the original Battlestar Galactica can be very hot-tempered - especially when it concerns Starbuck doting on other women. Other than that, she usually keeps a cool head on duty and being sweet and loving towards her father.
Doctor Who: Amy Pond swings between Harsh and Sweet when it comes to Rory; she begins very Harsh, calling him her "sort-of boyfriend", while still being sweet to him, but softens up considerably - being overtly affectionate while sometimes swinging back into her angry behavior - after watching him die. Twice.
Amy also treats the Doctor in this manner during her first episode, swinging between Oh my God it's my Doctor! and Twelve Years (and four psychiatrists)!.
Maya Hart from Girl Meets World qualifies as this towards Farkle, with heaps of snark.
I'm only looking out for your well-being, although I don't see why I should care when you plainly don't. I'd even be willing to help you do some exercises. —Not like that! Get your mind out of the gutter!
I do wish you'd spend a little more time with me... jerk.
...Let's get back to Tsundere, before you make this even more awkward.