Gord has myth and legends! So many legends! He was raised in the Kellid oral storytelling tradition; his mother's parents were the old tribe's skalds when they left Sarkoris-that-was for the eastern diaspora. Adventurers from the world over come to Mendev for a bit of crusading, and priests of all faiths, and he has talked to all of them and has heard (possibly garbled, definitely conflicting) versions of every culture's stories about the gods.
It would take days to actually recite them properly (and he's terribly out of practice and slightly ashamed of this), so how about a quick summary of some random stories he can recall on short notice. Ones about the gods actually doing things on Golarion, not the ones about Asmodeus being a fallen angel.
Rovagug, the Eater of Worlds, once threatened the whole universe with destruction. He ate several planes and planets before a coalition of the gods defeated him. They couldn't kill him, so they imprisoned him inside Golarion. (This was before recorded history.) Later, Sarenrae smote a city full of Rovagug cultists (she has said she's very sorry about this).
Earthfall was going to destroy the world but a moon goddess sacrificed herself by blocking it with the moon. It still destroyed civilization and ushered in a thousand-year Age of Darkness.
Aroden personally incarnated to kill the necromancer Tar-Baphon. (It didn't take.) He also fought some other threats, but Gord isn't sure which ones happened when he was a god and which when he was still an immortal human. He might have helped fight Treerazer, a demon lord who lives on Golarion.
Abadar incarnated as a pharaoh, or a series of pharaohs, to win Osirion's secession war from the Kelish Empire, and he has ruled it ever since. Gord isn't sure why he did this, exactly, but the Osirians are very proud of being ruled by a living god.
Nethys once sent a pharaoh dreams that drove him mad so he killed himself. (This was ancient Osirion, not to be confused with modern Abadaran Osirion.)
Desna killed a demon lord who had killed her high priestess. This was technically in the Abyss, but the priestess was killed on Golarion.
Gorum granted a mortal champion a boon: he would only die in battle. But the champion, being proud, declared he would never be defeated, and so thought he was immortal. (Gord thinks this might be a Gorumite heresy, actually.) This angered Pharasma, goddess of birth and death, so she sent her servants to fight and kill him. There are different versions of the story's end: sometimes the champion reigns undefeated; sometimes he is killed, but Gorum raises him as an undead, so that he may never be judged by Pharasma.
Milani supported the Galtan revolution. Gord isn't sure if she intervened in person, but she sent her herald.
Immonhiel is said to be always wandering Golarion in mortal form, helping and healing people, but no-one knows who she really is, so there are a lot of claims of sightings over the years.
Kurgess was an athlete and gladiator (Gord thinks exhibitional fighting is kinda gross if it doesn't lead to real fighting for a real goal, but whatever), and he impressed Cayden and Desna so much they made him a god. (Alternatively, some people say he was their son.) He enters tournaments under false names, invariably wins them, and then reveals his true nature and teaches the other competitors a new technique.
Achaekek kills people who try to become gods. There are actually fewer stories about him succeeding than about people ascending after he presumably failed. Maybe he's just a cautionary tale.
Of course, if you count tales about the gods' followers doing things that the gods empower them for, there's endless amount of them! The very strongest clerics can call down literal miracles from their gods and this has happened hundreds of times, at least. And lesser outsiders who are not gods often come to Golarion to do things, and some of them are definitely sent by gods as their agents, but of course it's hard to tell which.