The answer is no. No site has anonymous reporting that is reputable to the highest mod level. It is important that mods know who is reporting for the wrong reasons and also who is reporting well so as to then contact the reporter(s) about the issue if the mod feels the reporter needs assurance the issue is being dealt with of if the reporter themselves is in the wrong somehow (or just to elaborate on context).
IF IT'S ANONYMOUS, IT WILL ENABLE DDOS ATTACKS TO GO UNANSWERED OR NO ONE HELD ACCOUNTABLE EVEN THEIR IP OR ANYTHING!