I've been playing retro games for the past years, and here's some that might fit the criteria of forgotten cult classics:

• ScummVM:
  • The Bizarre Adventures of Woodruff and the Schnibble of Azimuth: It's a funny and interesting point and click game, use a guide though, there are some obtuse puzzle and pixel hunting
• TurboGrafx CD:
  • J. B. Harold Murder Club: a straightforward but interesting crime mystery game
• SNES:
  • Ihatovo Monogatari: an interesting no combat top down adventure game
• Sega CD:
  • Snatcher
• Sega Saturn:
  • Policenauts: I like Policenauts more than Snatcher, but both are interesting sci-fi visual novel like by Kojima
• Playstation:
  • Mega Man Legends
  • Mega Man Legends 2: both MM Legends have heartwarming light hearted stories and okay gameplay
  • Tail Concerto: similar to MM Legends, but gameplay is bit more basic. Features tons of cute anthropomorphized cats and dogs. Very lighthearted
• Playstation Portable:
  • Remember11: The last game in Infinity series, co created by Kotaro Uchikoshi who went on and created Zero Escape trilogy. Out of the Infinity series, this is probably the best one, it is more sci-fi than romance/dating visual novel, there's no longwinded slice of life section.

All of those games are either in English or have been fan-translated