Now that I think of it, you could make a fun gamble. Buy a JHS Bonsai, you get a fine selection of boosters and OD's in the same pedal. You also get an OD-1, which is said to be SD-1 archetype, but IIRC it's not entirely that and definitely a lowend cutter.
I've owned both the GT1 and GT2. J Rockett Archer pedal (silver one) because it lets the amp's character through and doesn't cut too much low end. Or, if you really want the best and have the $$$, an old DAM three knob Meathead Deluxe with the variable low cut filter on it. You can shave some lows and use it as a clean boost/mild OD. I've been through dozens of pedals with these two amps, and these were the best.