I need to get a list of all the files that only differ in case.

I.e., if I have a folder (with sub-folders) with the files:

one.txt

ONE.txt

two.txt

three.txt

three.TXT

four.txt

five/5.txt

five/6.txt

five/6.Txt

I want some bash magic that will spit out:

one.txt

ONE.txt

three.txt

three.TXT

five/6.txt

five/6.Txt