(Credits to Madisaurus for this! Permission was asked!)
Character permissions for fan-art/Commissions or something:

Please no :'D:
1: Please, I beg of you. Nothing NSFW or anything of the sorts.
2: No shipping of my characters with yours, someone else's, or a non-canon ship lore-wise. Fluff is okay as long as they're a friends OC and it's not romantic.
3: Nothing hateful or anything that targets another user/artist negatively.
4: Please no copying of my OCs (Fancharacters are not copying my OS [Original Species], alright?).
5: Draw them in a way that doesn't fit them (E.g. a cinnamon roll acting psychotic).

Yes:
1: Gore, blood, violence, etc, for characters that it fits for!
2: Ship art for characters who are canonically with each other.
3: Animations (be short).
4: Random stuff.
5: Drawing my characters with yours.
6: Changing designs to fit your style but have them still be recognisable (This one is very thin because I HATE them being drawn wrong).
7: Fluff with someone else's OC (e.g. snugglies) as long as they're a friends OC and it's not romantic.

Preferably ask before you do:
1: Kill off a character who isn't canonically dead.
2: Make it in the first place! I'm very possessive of them.
3: Use an outdated design of a character, or a design that doesn't reflect their current state.