Post art from artists who purged their stuff from the internet. If you can still find it in the usual places, that's fine, just as long as the artist clearly took steps to try and scrub their presence to the best of their ability.
Picrel, I've been looking for one specific (sfw) picture by Pynkblud (also known as Mr Steak) for a long time now. Pynkblud always had a habit of periodically deleting all their shit and never reposting it; AFAIK this last time (a few years ago) was the big one and they're unlikely to ever come back.