Here's another drawing for the San Diego Comicon Souvenir book. This is the one that actually saw print back in '04. To see the one that didn't you can click here. (I sent two so that I'd have a better chance of makin' it into the book. Ain't I clever;))
And if you're wondering why the likes of Zot, Cerebus, Concrete, Batman, Nexus and the Spirit are at Hellboy's birthday, it was just an excuse to draw some more of my favorite characters.
In silhouette in the back are even more if you look hard enough.