Nathan Fillion puts the "ham" in Captain Hammer. But he's playing a smarmy, self-absorbed superhero caricature—it would be impossible to portray the character any other way. Fillion remarked that it was the only time in his career a director had to tell him to be more of a ham.
Captain Hammer (singing while giving Dr. Horrible the finger): "Everyone's a hero in their WAAAAAAAY?!?"
Doctor Horrible himself becomes Doctor Hamible in the last act, during the song "Slipping", and Act II - Brand New Day is a delicious slice of ham.
Strong Bad: "Well, I heard a techno song one time that went like, 'Doom doom doom doom', and then this other part came in and it was like, 'Dudalado! Dudalado! Dudalado! Dudalado!' And there's always this high-pitched noise, you know, like a siren that's like, 'DOO-DA-DA-DIDDLE!! DOO-DA-DA-DIDDLE!!!' And then there's the obligatory old movie quote from some sci-fi movie, it's like, 'The system is down! DOO-DA-DA-DIDDLE!!! DOO-DA-DA-DIDDLE!!!!'"
Strong Bad: "WHY? WHY DO MY THIRTY-YEAR-OLD ELECTRONICS KEEP BREAKING ON ME???"
The Angry Video Game Nerd alternates between somewhat constrained and really exaggerated Unstoppable Rage (particularly during rants, and sometimes even silent, like his Kaiju impersonation during the Godzilla video).
Phelous in general, especially when he starts growling his words.
Diamanda Hagan could easily give Nella a run for her money. Ham-off away!
The Un-Cancelled Nostalgia Critic episodes include the two actors hired for Demo Reel, Malcolm and Rachel. They also ham up like there's no tomorrow, best case so far being in the Son of the Mask review, where they are the Devil and his daughter.
Mille Chanteau of Ilivais X is the queen of ham. If she's in battle, it's all but guaranteed anything she says is an epic speech of some kind, and it's not limited to then either. Of course, there's also Seyne (that comes with being a Sanger ZonvoltExpy though), most of the GEKICOM and STRUQ members, hell, even Iriana has her moments.
Snape, Draco, and Voldemort all qualify, with Snape being the most egregious example by far. Dumbledore is up there as well, especially when he starts lapsing into a Yiddish accent. Really, half of the play is the actors all trying to out-ham each other... which doesn't detract from it at all.
"Malstrom- World-wide sex symbol to women. When a new article appears, his mailbox gets flooded by the ladies demanding passion from him. "A business article on video games? That is so hot!" they squeal. Each Malstrom article also gains him a million dollars from jet-sitting super secret investors. Malstrom is also prone to self-delusions. ("Hey," he says, "if you are going to have delusions, might as well go for the really satisfying ones!")"
Both Egoraptor and Jon Tron have a good amount of ham in their works, so quite naturally the Game Grumps can ham things up, for instance breaking into song at quite a few moments and interacting with Barry for the Caption Humor.
Most Volus on Cerberus Daily News are this by default. But the standout case would have to be the duo of Jorgal Dwick and Terrorbyte. example
TotalBiscuit is a natural ham to begin with, so you can probably imagine how things get any time something excites him.
Daym Drops, providing SUPER OFFICIAL fast food reviews with even more ham than the food itself contains (which admittedly is not hard, since the food usually contains bacon, not ham). He once did a video in his normal voice, just to prove he actually has one.
While Cecil from Welcome to Night Vale has his moments, perhaps the best Night Valean example comes from Jackson Publick's Hiram Mcdaniels. Well, two out of five, anyway.
Green Head:Do you hear the beating of my terrible wings? Do you feel the flames lick at the corners of a life you once thought belonged to you?
Purple Head:AND YOU WILL NEVER HEAR IT! IT’S A SECRET! AND BURIED IN A SECRET PLACE!