The Avengers and the Fantastic Four were a part of keeping Hulk in check, as well as the Teen Brigade. In The Avengers #2 (November 1963), they called Giant-Man (Hank Pym) to help defeat a Space Phantom. They contacted the Avengers to notify them about the whereabouts of the rampaging Hulk in The Avengers #3 (January 1964).
A group of heroes, including the Avengers and the Fantastic Four, collaborated with the Teen Brigade to manage the Hulk's behavior. In The Avengers #2 (November 1963), they enlisted Giant-Man (Hank Pym) to help combat a Space Phantom. They notified the Avengers about the Hulk's movements in The Avengers #3 (January 1964).