Just know some of these are what are actually/probably are, the most of them are my imagination tho. Some of these may not exist cause I thought of them, or they could exist but I didn't know so I just made it up and it just so happened to already be a thing. I'm also thinking of aus where some of them have another side or 2 so thats why some of them seem odd/ are two things. Also is based off what their parents in this au could be. 

Dream: okay so dream himself i see him as a god of sorts. one of his other sides is an ender dragon and his other side is a demon. [ other sides are named Nightmare aka a red demon and Lucid aka a purple ender dragon]

Sapnap: Vampire. or maybe half vampire half werewolf aka that would be chaos since stereotypically vamps and wolves hate eachother

George: catboy george. thats all-

Bbh: Half demon half dark angel

Skeppy:

Tommy: ...hear me out- part dragon but its cause i have a dream and tommy as sibs au in my head and see one of dream's other sides as an ender dragon .-. imagine just little dragon wings and horns. red ofc.

Philza: Fallen angel or half angel half dark angel

Techno: ....A god [god of war,blood ect] and a pig-

Wilbur: Half siren half dark angel

Tubbo: 2/3 human, 1/3 wool ram

Schlatt: Half wool ram, half human

Quackity:...Shapeshifter *can be other people or full/part anime, usually is a wolf*

Eret: god/goddess of beauty and love, siren or maybe an elf of some sorts

Karl: god of time, half puppyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy-

Fundy: Born part merman part human but is now part fox part human ((i will explain the idea in a chapter and in a book))

Ranboo: Half Enderman half idk-

bonus:

Jared: dog boy [ thanks to @J-JARED- ]

this was meant to be in my au book lol but i wanted to do it here :] ill do one of what god/goddess they could be. i wanna write for some of these things veryyy muchhh. mostly a tommy and dream sibling au- and also a tubbo and dream sibling au with dadschlatt.