Psionic, anyone? Some sort of channelers with willpower based damage.
Drone Hive. Uses melee slot, every turn launches small drone, consuming some amount of credits. Replaces attack button with "drone barrage", which commands all currently launched hive drones to ram into target and explode. Intact drones can be refunded after combat.
Designator. Lock on target to call for artillery/air/orbital strike (only works outside for obvious reason). Can be used for whole assortment of attacks. And better be sure that you own shields are up...
Syringer. Can be loaded with all sorts of shit.