Personally I’d go with Independence Day if I had to pick a movie that felt the most 90s.
Pulp Fiction.
Wayne’s World.
Wayne’s World was trying to recapture Mike Myers’ childhood in the 70s and early 80s. So doesn’t capture spirit of the 90s.
Akira
Okay, it’s actually 1988, but it definitely got that 90s anime feel.
Definitely The Mummy starring Brenden Fraiser and Rachel Weisz
Reservoir Dogs (1992)