I haven't bought much art on this site but offsite I sometimes add watermarks to my favorite works.. like Really Heavy watermarks because hey hands off my characters.
edit: ^ above. these watermarks are just "i love them sm" written in various ways LMAO
As an artist: I watermark my designs but my headshots are 100x100 pixels size I just don't sorry 😭 I just add a littol signature on the side- watermarks don't stop tracers/heavy referencers what can I do pensivecowboy
ALSO people's toyhouses add their own watermarks automatically if they want to- so mmm yeah.
Design watermarks: "marshpup" + "unsold design" instead of "not yours" because it's more clear in my opinion.