def template_files(path, exts=None):
    """
    Return a list of filenames found at @path.

    The list of filenames can be filtered by extensions.

    Arguments:
        path: Existing filepath we want to list.
        exts: List of extensions to filter by.

    Returns:
        A list of filenames found in the path.
    """
    if not os.path.isabs(path):
        _path = os.path.join(determine_path(), path)
    if not (os.path.exists(_path) and os.path.isdir(_path)):
        return []
    if not exts:
        exts = []
    files = os.listdir(_path)
    files = [f for f in files if os.path.splitext(f)[-1] in exts]
    files = [os.path.join(path, f) for f in files]
    return files