Ganon is defeated at the end of pretty much every Zelda game, yet somehow he always comes back to fight another day. Usually the games are silent on how he keeps returning, but both the Oracle games and The Adventure of Link refer to a ritual by which he could be revived. The details are different, but there are similarities. In the Oracle games, the villain’s surrogate mothers Koume and Kotake light the Flames of the Dark Rites, then plan to sacrifice Princess Zelda to complete Ganon’s resurrection. When Link wins out against the Twinrova, however, they sacrifice themselves instead, making Ganon return as a mindless evil being.
According to the official timeline, these games take place after A Link to the Past, so it’s his death at the end of that game that they’re trying to counteract.
The instruction manual for Adventure of Link also refers to a sacrifice, but here it’s of the hero who defeated the evil being before, which would be Link himself. The Moblins plan to mix Link’s blood with Ganon’s ashes to bring their leader back to life, which is why the Game Over screen says “return of Ganon.” Since Link is dead, he can’t go on to defeat the monster. I’m not sure why Ganon’s minions couldn’t obtain some of Link’s blood without killing him, but that’s apparently the way it works.
Finally, I’ll note that the plot of one of an episode of Captain N called “Quest for the Potion of Power” had Mother Brain attempting to revive Ganon with the titular potion. Here, Ganon was still alive but severely weakened, and giving him the potion brings him back to full power.
He doesn’t last very long, though, as Captain N and Link use reflective magic to direct his own power against him. In a later episode, “Having a Ball,” Mother Brain claims that Ganon is asleep, and it’s established that anyone who holds the Triforce can command his minions.