Git Branch Completion in Bash
You can get git branch auto-completion in bash. Sometimes this is configured out of the box, but it didn't work for me using homebrew's git.
If you are using git installed via homebrew, git-completions.bash is located at /opt/homebrew/etc/bash_completion.d/git-completions.bash (or better yet $(brew --prefix)/etc/bash_completion.d/git-completions.bash for reliability). You just need to source it in your .bashrc or .bash_profile with:
test -f $(brew --prefix)/etc/bash_completion.d/git-completion.bash && . $_
(This is a cool shorthand syntax to test that the file exists, and if it does, source it. $_ refers to the last argument in the previous command, in this case the full path to git-completion.bash)
Now you can tab complete all your branch names in git checkout, git rebase, and more!