Here's a ranking for quirk strength, it's ranked on how much destructive power one quirk can produce.
SS - Impossible (10,000 ~ 20,000) Never been achieved
S - Legendary (10,000 ~ 6,000) All Might
A - Powerful (6,000 ~ 3,000) Endeavor, Best Jeanist, Overhaul (villain), ect
B - Decent (3,000 ~ 1,500) Kamui Woods, Gang Orca, ect
C - Average (1,500 ~ 500)
D - Weak (500 ~ 100)
E - Useless (100 ~ 0)