The Heroic organization offers games using many different rules systems. Some of those rules systems are listed below (some of which you must be a member to access.)

To become a Member of Heroic, please join here.

Any game, no matter the rules system chosen, must follow the Fundamental Rules of Heroic and if that game wishes to have transferability (to any degree) to other games, they must also follow the Fundamental Transferability Rules.

Fundamental Rules of Heroic
Fundamental Transferability Rules

Game Systems available under Heroic
The Heroic Core Rules System
Ravage
Accelerant