Blizzard has a passionate fanbase, which is why the developer is able to hold a yearly convention devoted to its slate of games. But those fans don't attend BlizzCon just to see what's new in World of Warcraft and Diablo and so on; they also want to dress up for Blizzard's annual costume contest.
The photographer York in a Box helped run the cosplay festivities this year, and as such he was able to take some pretty incredible pictures. Case in point: the group shot above (see the full-size image here), featuring dedicated Blizzard fans dressed up as their favorite characters from every game in the publishers line-up. There's even a bunch of characters from Overwatch, which was just announced at last year's BlizzCon.
The most obviously impressive bit of cosplay in the shot is the giant Hydralisk from the Starcraft games on the left-hand side. I saw that one in person and can confirm that it was incredible.
Other favorites: a girl just to the right of center who is cosplaying as the original World of Warcraft box art, a near-perfect version of Heroes of the Storm's Sgt. Hammer in the middle left and a dryad complete with a pair of back legs on the right-hand side. Some incredible work here.