Subgroup
From Transformers Wiki
A subgroup is nearly any category of Transformers characters aside from their faction. While some subgroups, such as Dinobots and Commandos are unique to a particular faction, others like Pretenders and Fuzors are not. Members of a subgroup will share some common trait. Example traits include the Aquaspeeders' color changing, the Omnicons' control of energon, the Rescue Bots' shared function of rescue squad, and the Terrorcons' beastly alternate modes and combined form of Abominus. Of course, sometimes a subgroup can just be a result of disparate characters being thrown together by fate, such as the Substitute Autobots.