In Ilinaire, anyone can be, unless stated otherwise.
In Illiniare, anyone can be, unless stated otherwise.
In Yorune, only humans.
In Sintane, humans, elves, Teiosians, orcs, and dwarves.
In Nozenrote, only humans.
In Ninsharra, only humans, Shunians, Teiosians, and elves; followers of Ninsharra/loyal to the crown.
In Geirte, only humans.
In Kalevritia, only humans.
In Puuria, only Puurians.
Aswalder, Melchoria, Teios, Orc, Shunian, Yan'shi, Ishanad - racial abilities.
Dwarf, Melchorian, Teiosian, Orc, Shunian can choose an additional origin bonus.
Yan'shi and Ishanad - no.
Also forgot the Tilians and elves, but I'll mention them later.