Free For All:
AoS should not only include team-based warfare, but lone wolf warfare where a player picks a specific color for their soldier, deploys, then runs around, surviving, and at the end (usually concluded by a time limit, or kill limit.
Last Man Standing:
A variation of Deathmatch, but when a player is killed, they immediately switch to spectator mode and stay until a player kills off all the others, thus crowning him the victor, sort of like Hunger Games. Again, players can choose specific colors of their liking.
Medival Mode:
From that one game with hats. Of course I'm alluding to TF2, or Team Fortress 2. Medival mode is a variation for all game modes, and only allows players to use their melee weapon, the trusty spade. This allows players to get more up close and personal, as opposed to sitting in trenches or dens, sniping away.
I'm sure one of these have probably been suggested before, but I'm just getting it out there, so hopefully Ben could see.