Hell I've been in photos of atleast 1/4 of those (as the victim usually and enjoying it) and have done atleast half

The scene already has a sensible rule: safe, sane, consensual - the 3rd being the most important as far as I'm concerned.

Any porn that makes the fact it is consensual obvious should be fine (is why anvil bdsm has some fairly hard BDSM scenes 18 rated not X rated)