I repurposed stock deities, and took heavy inspiration from some threads on this forum. So some people might recognize some of these ideas.

Tharizdun. The original deity. He was all there was, and all powerful. Until one day he conceived of something that was NOT him. Bam, Taiia came into being. She was everything he was not, and he hated her. So he created space and time just to have somewhere to expel her.

Taiia. The deity of good, chaos, passion, life, and destruction. She not only embodies existence, but also change, for good or for bad (though she's mostly regarded favorably). She immediately began to fight Tharizdun once she came into being.

Io. The deity of protection and law. A deity forged by Tharizdun to try to destroy Taiia, as he could not reabsorb her at her full strength. Designed to rip apart the foundations of what made Taiia exist. And he almost won. But while he and Taiia fought over eons, they grew to love each other. She created wonderful things that had brand new rules that were much more intriguing than Tharizdun's nothingness. And so together they turned against him.

Together, they tried to lock Tharizdun away, but they couldn't do it alone. So Taiia and Io had "children". They created new concepts and filled space and time with them. They started the cycle of life and death, and drove Tharizdun mad, as even a speck of dust was offensive to him, and now the universe teemed with "not him" that he hated. (That madness manifested as the Far Realm.)

Shar. No resemblance to D&D Shar. I just liked the name. Goddess of death.
Gaia. Goddess of life
Cyndor. God of civilization, of travel, and of time.

Together, they locked Tharizdun away. They inverted space and time around him, locking him in simultaneously an infinite void and an infinitely small container. But they don't realize that Tharizdun was capitulant in this. From his perspective, he locked them away. The things he hates are quieted, but not gone, and not forgotten. He plots his vengeance, and seeks to bring all things to an ultimate end. Meanwhile the deities maintain the cosmos they created.

There's more to it, but that goes into more cosmology than Pantheons. I took away the deity status of other gods, and made them eidolons, powerful progenitors of concepts or peoples. Corellon Larethian and Moradin exist, but they're not "gods" in my world.