I think my whittled-down NES ROMs dir that included probably a dozen games that aren't very good but have strong nostalgia value for me, plus a couple Japanese games in unofficial translation, ended up being around 80 entries. I'd probably cut that down to about 50 if I were setting something up for someone who wasn't around back then. SNES comes off a little better but my curated-for-others list would probably be around 70-80, including quite a few translated games.

Part of it's because a lot of "greats" have better versions elsewhere (arcade, for games like Mortal Kombat, Gameboy Advance in a lot of cases especially for RPGs, et c.) and part of it's because there was just a lot of crap on them (I think the NES had over 1,000 distinct games).

That's still a lot of good games.