I've been looking at Tumble's pic and been thinking "What's her quirk?" and I came to the conclusion she's either self-healing based leading to the personality of someone willing to take on the world's problems and take street rats as sidekicks, or if she's something more weird maybe she can absorb kinetic energy and convert it to power. 

As I was about to his post I realized the second one might need explanation: for example she gets punched and then the force of the hit is added to her strength. So if say, All Might punched her (and somehow survived) she would have the strength of that blow. Then she gets punched and punched and gets stronger and stronger which she can then unleash all at once.

EDIT: And now this may all be missed. Good timing me :P