Counter-agents refer to individuals or entities that work against or oppose a particular agenda or mission. Conversely, antonyms for counter-agents could include "supporters," "allies," "collaborators," or "advocates." These individuals or groups work in tandem with one another to achieve a common goal, rather than opposing it. The term "counter-agents" often implies an adversarial relationship between two opposing sides, whereas the antonyms suggest a more cooperative approach to achieving success. In short, the antonyms of counter-agents denote individuals or groups that work towards a mutually beneficial outcome, rather than working against each other.