To be specific, metallic or chromatic dragons for an example. I know mindflayers and beholders and such are way off the list. But is the concept of dragons in distinct categories like this too similar to be used to any extent?
P.S. Respectfully, please don't give me the standard "just make something new". I know that solution, but this isn't a major story point, just world-building that might be brought up in conversation by characters, and I don't want to be sued for my character saying "Did you see the evil-looking black dragon in the swamp?"
(Edit) I think I need to make a clarification since it seems it depends on a case by case basis. I want to include a dragon similar to the Steel Dragon. I don't care about it being steel, I can easily change that, but the lore about dragons pretending to be humans I love. Now, their is a lot of lore about dragons pretending to be human, but not to the extent that a steel dragon does. So that is what I really want to know.