For me, it was the game Rocket Jockey released by Sega Soft in '96. It was perfect. The game featured a surf rock soundtrack by Dick Dale. The entire premise of the game was to ride around on rockets and using long cables to yank your opponents off theirs. Referees were also fair play. I don’t think I’ve met anyone else who has played the game, so if you have, let me know!
Doom, total classic. In that same vein, did you ever play Hexen? I recall it being a pretty cool medieval/ magic Doom.
And of course, unreal tournament. Although that was later. It had a Linux port which is why I played it.