Post Tournament of Power rosters you think will make up the field, remember there's a limit of seven entrants and they have to be mortal, so no alicorns, no Tamers12345, and probably no Bartleby because there's probably a by-law that excludes him from competing because it's basically cheating to have him on your team. Also it's multiversal so expect a bunch of other franchises to join in. Here's what I've got so far:
MLP
>Twilight Sparkle
>Trixie*
>Flawless
>Rainbow Dash
>Rarity
>Big Mac
>Care Package
SU
>Sonic
>Manic
>Sonia
>Knuckles
>Queen Aleena
>Dingo
>Flora
PPG
>Blossom
>Bubbles
>Buttercup
>Brick
>Boomer
>Butch
>Mojo Jojo
DBZ
>Goku
>Gohan
>Vegeta
>Krillin
>Piccilo
>Frieza
>Broly
Zatch Bell
>i don't remember any of their names but just pretend there's seven of them
*subject to change due to her Pegacorn nature but so far I haven't seen any indications it makes her immortal, it seems like more of an elevated state of self like going super saiyan