Fzf (see https://github.com/junegunn/fzf) completion for git checkout (which I have aliased to co). See (a previous version without origin removal) in action here: https://asciinema.org/a/DCZH8q4mZHr79uVGZcM5RCtRb

git_complete.sh

_fzf_complete_git() {
    ARGS="$@"
    local branches
    branches=$(git branch -vv --all | sed "s/remotes\/origin\///g" | sed "s/\*/ /g")
    if [[ $ARGS == 'git co'* ]]; then
        _fzf_complete "--reverse --multi" "$@" < <(
            echo $branches
        )
    else
        eval "zle ${fzf_default_completion:-expand-or-complete}"
    fi
}

_fzf_complete_git_post() {
    awk '{print $1}'
}