A lot of fantasy goes with Tolkien explanation of fantasy racism being the result of ancestral grudge.
Then you got Dungeon Meshi which is like:
"Elves and Dwarves hate each other because their respective empires make up 2/3 of the imperial core and are stuck in a cold war as the planet runs out of uncolonized land to grab. Elves are able to live in pastoral paradise because they've horded most of the settings farm-able land and natural capital, displacing and mass murdering any natives in the process. Orcs and goblins are hostile to other races because there the primary targets of an ongoing slavery and genocide campaign. The dividing line between human and inhuman is arbitrarily assigned via a phrenological pseudo-science that quickly falls apart when questioned by anyone who wasn't indoctrinated into it since birth."
Here’s my personal recommendation of a YouTube Channel to check out:
Coelophysis "blushes" by flushing the skin overlying its exoparia with blood.
YES! MORE!
If you haven't checked out David James Arsmby's work yet, I suggest you start doing so right this instant!