CSF (Config Server Firewall) can block several anonymous via iptables - or you can use @tenantsStop Country Spam (which has the ability to detect proxies). Only problem with that is it can block people from browsing via mobile devices.
I've moved my servers over from fail2ban to CSF recently and really like it (but I get about 200 alerts - via email - a day from the 3 servers and 4 VPS's I have it on).