Now that Multimouse is revealed, I'm making a list of alternate mouse abilities:
Pockets (wishful thinking). Literally just hammer space pockets all over, where she'd packrat whatever vaguely useful objects she can find.
Better-Mouse-Trap. À la Tom & Jerry. More practical than power, a matter of application. Goes with above + pure ingenuity. Absolutely convoluted contraptions. Doesn't have luck factor, does retain crazy factor, but bigger.
Stealth! Sneaking, sleuthing, spying...
Squeezing through any space (kinda sorta canon...).
Combining miraculous (without wearing them I mean).
Or powers (the little spaces looked like they could fit a kwagatama).
Mimicking a power, miraculous or akuma.
Bonus: Idk who's choosing the catchphrases, but I would've liked "scurry up/scurry off". I would've settled for anything other than what we got really.