Agents have one Signature Ability which they get for free each round.
Riot was aiming to launch the game with 12 agents, but only 8 were available in the early press builds. The March 29, 2020, private event introduced Breach. Since the Closed Beta launch on April 7, 2020, Raze was added along with the map Split, bringing the Agent total to 10. Five agents are available at first launch, with two more that can be easily unlocked by leveling up in the game. More agents can be unlocked by taking Contracts and gathering XP on them.
It is the intention of the developers that one agent be released per act.
There are 4 types of agents each with their own tactical usage-
List of Agents