Can confirm Fistful of Frags is great fun. Adding to the list: the new Unreal Tournament, No More Room In Hell, Halo Online (search for it on reddit, it's basically Halo 3 on PC).
I've never tried: Brawlhalla, Tribes: Ascend, Dirty Bomb or Loadout
Brawlhalla is a great game, however you need to understand the game and put a lot of hours in it to really see its true value. And you need to get passed the "noob just spam-signature-move-because-other-noobs-cant-dodge" part. After that it is an amazing game.