What are some of Galactus's most notable adversaries?

Galactus has a long list of formidable foes. Some of his most notable adversaries include the Silver Surfer, who acts as his herald and a moral compass; the Watcher, who observes Galactus's actions; the Beyonder, a powerful cosmic entity who challenged Galactus; and various cosmic heroes and teams attempting to stop his planet-devouring activities.