>>149698264
Just got caught up on the GOTG series and there's a couple eps with teen and loli Gamora. She isn't really fighting as such in either though the teen version did get briefly infected with a symbiote and went wild.
Young Tana Nile also shows up in a couple and does do some fighting though in her first appearance she's only hours away from her Rigellian bat mitzvah. Definitely counts as a brat though.