The MXR MC-401 Custom Audio Electronics Boost / Line Driver pedal is a great clean boost for your pedalboard. The CAE Boost is great for boosting signal on long cable runs too. Check out the The MXR MC-401 CAE Boost / Line Driver.
The MXR M-133 Micro Amp is an affordable clean boost pedal designed to give a boost to your amps front end or balance out instruments with different output levels. Check out the MXR M-133 Micro Amp and give your rock a boost!