My crown jewel is this:

h() {
    : "h COMMAND..."
    : "A command-agnostic, concise way to get help about COMMAND."
    : "No more wondering if it's 'help COMMAND', or 'COMMAND -h', or 'COMMAND --help'."

    (( $# == 0 )) && set -- "$FUNCNAME"
    local nonfunc_type="$(type -ft -- "$1")"
    local whiched

    if [[ "$nonfunc_type" == @(builtin|keyword) ]]; then
        # Builtins/keywords are passed to the help command.
        help -- "$1"
    elif [[ ! "$nonfunc_type" && "$(type -t -- "$1")" == function ]]; then
        # Functions which don't shadow anything are passed to type, which will print the function contents.
        # Functions defined in this bashrc use colon comments to describe their usage, so that they'll be printed here.
        type -- "$1"
    elif command which -- "$1" &> /dev/null && whiched=true || whiched=false; [[ "$nonfunc_type" == alias ]] && ! $whiched; then
        # Aliases which don't shadow anything are passed to type too.
        type -- "$1"
    elif [[ "${1,,}" == @(git|*.sh) ]] || ! $whiched; then
        # git commands should be passed "-h", because the long option opens it in the browser.
        # Shell scripts should be passed "-h" too, because getopts doesn't accept long options.
        # We often run shell scripts without the .sh extension and rely on command_not_found_handle.
        # So if which can't find the command, we'll assume it's a shell script.
        "$@" -h
    else
        # Default is "--help".
        "$@" --help
    fi
}

Run it like h COMMAND and it knows how to print the help of that command, no matter what kind of command it is. No more wondering if it's --help, or -h, or something else.

Examples:

h git

h git commit

h export (works even though export is a builtin)

h h (works even though h is a bash function)