There are definitely Arch-Angels (Uriel, Micheal) which leads me to believe that angels are also kicking around. The devils would be Nicodemous and the rest of the coin crew. Demons are the denizens of Down Below. Fairies and other supernaturals are living or tied to the Never Never (vampires (at least white court but I think reds are there too))
The White God is God, big 'G'. He/she/it has not been revealed though and may not actually exist or may not an active player in the story. The Outsiders would be the ancient beings or old gods like Cthulu although I don't remember him actually being named but he's still the best example I can think of of an ancient being or an old god. I suppose beings like the titans might fit into that category (Kronos and his crew). These would be the beings that the Gatekeeper is keeping an eye on the gate for.
We know at least one old god (Odin) is kicking around in the real world with his Valkyries. There are many others potentially playing a part or maybe they just retired to the Florida of the Never Never after their worshipers dried up. Personally I don't like calling him an old god but I can't think of anything better. Middle-aged god maybe?
These are just the Western supernaturals to. I'm not very familiar with Eastern mythology but I do know that Indian religion/mythology has a ton of gods. I don't know if they have a creator god which I suspect would be linked with the White God to wrap things up in a nice little package.