I noticed that Github offers an option to automatically delete head branches when PR was merged. This can be pretty useful for larger repositories where cleaning up your workspace can be as easy as doing
git pull --prune and then deleting all branches with deleted tracking counterparts. To find those you simply issue
git branch -v | grep '\[gone\]'.
I propose to enable this, it is getting out of control and even with my git xcleaner tool which I wrote it is hard to keep up with many branches which haven’t been merged yet.
BTW if you want to cleanup your branches in an interactive way, here is the tool I wrote some time ago: