Do's
General
Fan art
Species/Type
Humans
Anthro
Feral
Werethrope
Aliens
Other (goo, monster, etc)
Mythical creatures

Don't's
General
Political / Real Life figures
Species/Type
Skeletons
Skinwalkers / Horrorifying Imagery
W*ndigo
Inside bodies / innards / Internal shots
Hardvore / Hardgore

If it's not on this list, just ask first.