from typing import List


def get_available_signatures() -> List[str]:
    """Return a list of available signatures.

    Returns
    -------
    List[str]
        List of all available signatures.
    """
    signatures = [
        "high_q_freq", "high_q_dur", "low_q_freq", "low_q_dur", "zero_q_freq", "q95", "q5", "q_mean", "hfd_mean",
        "baseflow_index", "slope_fdc", "stream_elas", "runoff_ratio"
    ]
    return signatures