Disclaimer: I'm not good at these games. Just picked up a Neo Geo 2-slot, so I've been experimenting. Some of these are just based on fun factor, but aren't great fighters per se
Street Fighter II
Killer Instinct
Last Blade
King of Fighters 98
Tekken 2
Clay Fighters 2: Judgment Clay (needs an arcade version if there wasn't one)
King of the Monsters (beat em' up or fighter?)
Primal Rage