TLDR, assuming adaptive sync with LFC: A good floor for "smooth enough, I guess" is 50 FPS. But if you want the "genuinely smooth" feeling? 70 FPS is ideal. A good "endgame" target is 200 FPS. But the more FPS you can get, the better - there's no "human eye can't percieve above x FPS" - the limits for human perception are so high it's irrelevant to any discussions about FPS.
Gaming has, for as long as we can remember, aimed for the 60 FPS mark as the target. But we know that number isn't based on any biological observation or objective limit but rather is borne out of convenience, since most displays, TVs and monitors alike, maxed out at 60 hz. Not the mention the infeasibility of presenting at arbitrary sub native refresh rates on fixed refresh rate displays.
However, with the advent of cheap high refresh rate monitors (you can get a 144hz Freesync monitor for like $100 at this point) and TVs, and adaptive sync technologies that make it so that sub native refresh rates present just as perfe