Man, there's no telling what a given group will give you on dA. And the group management is for shit, too. I can never remember exactly which groups to submit a given post to, since they don't all show up in "history". However, I do recommend these for looking at:
Any you'd recommend? I'm also trying to get a big bang group up and running—if you create art for bangs or challenges, come by ArtForBigBangs.
Sample fandom-related submissions:
The Pencil Club: