@yora "Outside of Win/DOS, Amiga, and the Nintendo, Sega, and Sony consoles"
I take it you're lumping home computers in with consoles here? And Commodore's other home computers, like the C64 and VIC20, in with the Amiga?
"which systems had the best catalog of games that made them worth having in the 80s and 90s?"
In the '80s, too many to mention. The ZX Spectrum, MSX, Videopac/Odyssey 2, ColecoVision, Atari ST/7800/8bits, the BBC Micro, the Apple ][ series...
There were even a decent number of games on the Mac.
"From 1990 an onward, there seem to be very few famous games that were originally developed for those other systems rather than being ports."
I'd put the date closer to about 1995 rather than 1990.
In the early half of the decade, the Atari ST was still seeing new releases. The Lynx had a whole bunch. NEC TurboGrafx and its progeny. From memory, Need For Speed and other titles were originally released on 3DO.
After about '95, the computer world basically consolidated around the Windows PC, with the Mac holding on by its fingernails.
And likewise, PlayStation crushed everything else in its path including eventually Sega, with Nintendo holding on.