Toribash
Best board would be ToriPrime (if you got it).

Otherwise, I think the arts or off-topic section would be fine.
I'm only cleaning here..
To the fact that you don't have ToriPrime, and I know the art and texture forum wouldn't allow this.

Your best bet is either not doing it at all, or PMing people one by one to sign it.

"Dear reader, I hope this email finds you before I do."