Well a few of TFs have been shown to collect stuff as well - Rung for instance collects Ark ship models - similar I guess to how we collect model cars or Hotwheels, another character is Shortround, who collects... Transformers or I guess action figures of their kind, kinda like how some of us collects HotToys of their superheroes. . As a group I can deduce that the combaticons collects ammunitions, like a gun club or something hehehe, although Swindle keeps pilfering them hahah.