Convert list/tuple of arguments into just arguments
You could use itertools.compress in combination with the tuple

def get_all_users(times=False, groups=False, ips=False):
    """Get a list of all users online"""
    arguments = ("clientlist", "times", "groups", "ips")
    selectors = (True, times, groups, ips)

    return ts3conn.exec_(*itertools.compress(arguments , selectors))


or in python 3.6+, using the retained insertion order of dicts (earlier versions can use an collections.ordereddict

def get_all_users(times=False, groups=False, ips=False):
    """Get a list of all users online"""
    arguments = {
        "clientlist": True,
        "times": times,
        "groups" : groups, 
        "ips": ips,
    }
    return ts3conn.exec_(*(key for key, value in arguments.items() if value))