Not a head canon but my own setting Humans are interesting.

Since all gods were once mortals in setting. The setting implies evolution as some of the dragon gods remember proto-humans and talk about how the divergence between humans and the elves was caused when they settled the fey and the material with the elves then offshooting repeatedly post that into the various types.
The head of the dwarven pantheon it is assumed was well a dwarf who magically granted his descendants the same special abilities he had leading to the divergence of dwarves.
Well the head of the orc pantheon took a collection of humans and dwarves who would become the orcs.
Halflings are a modern off shoot of humans. Goblins are a similar offshoot but to orcs. Gnomes are a similar offshoot but to elves.
Tritons are early humans who adapted to the plane of water without infusing elemental energy. With the sea elves being a interbreeding of them and elves.
Centaurs are assumed to be a mage who granted a nomad clans wish to forever be apart of their horses. And would develop into the culture you later see, along with some druids messing around leading to off-shots like elven centaurs who would eventually develop deer traits.
Minotaurs are implied to be the sons of the first centaur god after he shagged a herd of cows. Others say the first minotaur shagged a group of horses and made centaurs. Because the two are one deity.
Kitsune are the descendants of humans and folk spirits becoming their own distinct lineage both fox spirit and not.
Catfolk no one knows some guess they were a mages attempt to prove evolution with cats. But that would raise the question then why do dog folk have a deity but cats don't. Or why the rabbit and otter folk both also don't have a god.
Merfolk are suspected to be tritons and/or sea elves who modified themselves or magically conceived with sea life