Well, I’ve got a whole bunch of (more or less) game-based webcomics.
Some videogames, some tabletop, some gaming in general… And so on.
Awkward Zombie does comics about various games.
Castle Vidcons is sort of… Game consoles as medieval noble families bickering with eachother.
Ding! makes fun of WoW.
Dungeons & Denizens is a D&D parody (surprise).
GU Comics has one panel strips either based on in-game or meta-game jokes.
Nerf Now has mostly done TF2 storylines, but also a short Starcraft story, a L4D arc and a bit more.
8-Bit Theatre, which everyone around here should at least have HEARD of. Started as a Final Fantasy parody, now it’s a huge… Whatever it is.
Order of the Stick is about the adventures of a D&D party called “The Order of the Stick” (duh).
Penny Arcade. 'Nuff said.
The Chronicles of the Flaming Ruby. A WoW comic about the comic’s creator’s (more than a little) whacky guild.
The Villain which, sadly, hasn’t updated for years, is a very witty parody of the Final Fantasy series in general with an INSANE amount of references to just about everything.
Turnsignals on a Land Raider. Based around Warhammer 40K and the two Land Raider crewmen Kren and Frep.
Yet Another Fantasy Gamer Comic. Also D&D based, but most of the cast are actually monsters instead of adventurers.
…Well, those are the most gaming-related comics I can find in my list of webcomics.
I guess I could also include:
Commisioned which does a D&D storyline that updates once a week.
Goblins. While it is not very game-y, it is clearly based on D&D, with quite a lot of jokes in that direction. Especially early with the dumb (one of them, at least) adventurers whose name I forgot.
LFG which is a very funny comic which seems pretty clearly inspired by WoW, to me.
Nodwick isn’t too much of a game comic. It more closely pokes fun at fantasy in general, but it has some definite D&D moments too.
Supermegatpopia’s “By Way of Booty Bay” is a collection of WoW comics by the author/artist.
But yeah. Those are the gaming related comics that I read at the moment, at least.
EDIT: I might have something more at DeviantArt. Haven’t checked DA for a while, so I can’t remember what I used to check there.