Is it possible to get info about how much space is wasted by changes in every commit — so I can find commits which added big files or a lot of files. This is all to try to reduce git repo size (rebasing and maybe filtering commits)
You could do this:
git ls-tree -r -t -l --full-name HEAD | sort -n -k 4
This will show the largest files at the bottom (fourth column is the file (blob) size.
If you need to look at different branches you'll want to change HEAD to those branch names. Or, put this in a loop over the branches, tags, or revs you are interested in.