The tier system I have in place for my own multiverse setting I'm starting up might be bad to try and get multiple people balancing characters well based off it but here it goes just in case.

A score of 1 represents the fighting power of a normal human. Each rank is 8 times more powerful then the last rank. Lets say Bruce Lee is as good of a fighter to take on 10 normal humans (you could make an argument that he could fight more but that's besides the point for the example). This would put him into E rank (the ranks found below with how many normal humans they could take on). There are three numbers in each rank to offer further distinction. The first number is just E rank, the next E+, and the last E++. Bruce Lee would be a simple E rank due to not being able to fight at least 16 normal humans. There are special ranks above S for legendary, gods, etc. Of course an A rank compared to an F rank being able to be roughly 33,000, these numbers seem to loose purpose after a certain point but still pretty good in knowing that they can fight around 8 B ranks.

F- 1, 2, 4
E- 8, 16, 32
D- 64, 128, 256
C- 512, 1024, 2048
B- 4096, 8192, 16384
A- 32768, 65536, 131072
S-262144, 524288, 1048576