git - Tags with the same name with a branch

First, we extract all the tags:

git tag | sort > tags

And branches, if you want to check this with local branches:

git branch | sed -e 's/^[ \t]*//' | sort > branches

Or branches of a specific remote, like origin

git branch -r | grep origin/  | sed -e 's:^[ \t]*origin/::' | sort > branches

After extracting tags and branches (in sorted order), we find the common lines in these 2 files:

comm -1 -2 tags branches > bad-tags

And view the file bad-tags
Then we can delete all of them:

cat bad-tags | xargs git tag -d