I found Aurorus pretty handy for my Rock Mono! If your team has some holes against Special Attacks, Aurorus is pretty solid with Light Screen, it also has access to Nature Power and Snow Warning which would definitely come in handy.
Cryogonal could also be good too, both good speed and access to Rapid Spin to remove obnoxious things like Stealth Rock and has really high Special Defense, Ground immunity and access to Recover will help out a lot too.