By US release date. Sort of cheating and naming 3 total.
90: GoodFellas & Isla das Flores (Runner-Up: Close-Up)
91: JFK & The Double Life of Veronique (RU: 35 Up)
92: Malcolm X & Europa (RU: Unforgiven)
93: A Brighter Summer Day & Baraka (RU: Naked)
94: Pulp Fiction & Fresh (RU: Hoop Dreams)
95: Heat & Se7en (RU: Leaving Las Vegas)
96: Fargo & The Georgetown Loop (RU: The People Vs. Larry Flynt)
97: Good Will Hunting & Jackie Brown (RU: Public Housing)
98: Mother and Son & The Thin Red Line (RU: Rushmore)
99: Magnolia & Being John Malkovich (RU: Rosetta)
1990: Goodfellas & Metropolitan
1991: Hearts of Darkness: A Filmmakers Apocalypse & Barton Fink
1992: Unforgiven & My Cousin Vinny
1993: Naked & A Perfect World
1994: Chungking Express & Three Colours: Red
1995: SEVEN & Dead Man
1996: A Moment of Innocence & Bottle Rocket
1997: Princess Mononoke & Perfect Blue
1998: Rushmore & The Big Lebowski
1999: Ratcatcher & All About My Mother
I think the 90's may be the best decade for independent and foreign cinema, i think it may be the worst for mainstream though which it's most praised for nowadays. Nearly every popular film i return to from that decade is horribly dated in so many ways that other decades aren't, have to suspend much more than disbelief to accept some of those films. I have alot of nostalgia for the decade since i had siblings older than me that introduced me to those films growing up so i love alot of them despite this, but yeah it's definitely overpraised as a Blockbuster Utopia; if such a decade exists it's easily the 80's their dated flaws are actually fun not awkward.