We know next to nothing about female gladiators--gladiatrices, as modern scholars sometimes call them, though the word is unattested in our literature. We have textual references to feminae or mulieres in the arena as combatants, but they're few and far between. The presence of women at the arena in and of itself isn't necessarily all that unusual--Martial mentions an actress dressed as Venus--but as fighters it's less common. Cassius Dio mentions women hunting animals during the dedication of the Flavian Amphitheater, and the Satyricon has a passing reference to female charioteers, but these sorts of references are very rare. More common are mentions of noblewomen (and men) being impressed by emperors to participate in the games--Nero in particular was a favorite target of these accusations. Juvenal has a puzzling reference to a mulier (used disparagingly--elsewhere in Satire 6 he speaks of degenerate women as pissing themselves and having orgasms in the middle of the theater because of mimetic performances, and...it's a particularly misogynistic satire, even for Juvenal...) training for the arena, with full armor and stuff, but he doesn't really say much besides lament that good ol' Roman morality is gone. His comment is about all we know about female arena-fighters, and it's not very helpful. Besides that there's a decided lack of epigraphical or visual evidence--to my knowledge the only certain depiction of these feminae is this inscription, which is itself rather puzzling (why is ἀπελύθησαν, the verb in Greek used for a fighter who has been granted a missio, in the plural? Why is it there in the first place if the inscription depicts a fight in progress or one that has not yet begun?) but in any case tells us nothing about the actual fighters themselves

How and where did you get the idea that there were some, if any?