One of my favourite classes in City of Villains was the Mastermind. We have pets in this game but we should expand them. In the following power categories we can gain the following minions.
Robot Behemoth: A bruiser heavy hitter that can supplement the munitions bots with hard hitting attacks
Demon Lord: Call a terrible demon lord as an upper level power. This specifically calls a demon lord and no lesser demon can be called.
Demon Legion: You summon a trio of demon warriors that are uncontrollable like the shadows.
Zombie Brute: A powerful undead attacker
Lich: Call on a fearsome Lich to aid your undead forces with darkness and infernal attacks. Condemn, Shadow Embrace and life drain
Call Soldiers : Summon 3 uncontrollable pet soldier units with munitions
Call Lieutenant: Summon a powerful soldier ally. Controllable munitions based pet with some gadgets
Call Mafia Thugs: 3 uncontrollable Mafia units, uses munitions
Call Mafia Captain: The Mafia version of the Lieutenant, munitions user
Light Armored Samurai infantry