How can I find all of the distinct file extensions in a folder hierarchy?

Question

On a Linux machine I would like to traverse a folder hierarchy and get a list of all of the distinct file extensions within it.

What would be the best way to achieve

Answer 1

I think the most simple & straightforward way is

for f in *.*; do echo "${f##*.}"; done | sort -u

It's modified on ChristopheD's 3rd way.