i strongly suggest a ProCo RAT. it can go from slight overdrive to brutal with its gain control, but adding an input attenuator is a good idea for most overdrives used with synth-drum-electronic gear. i think a big muff can be quite good on drums as well, especially with the tone and gain down a bit.
a DOD 250 is also quite mellow, being bright, but not aggressive.
cheers, Iain