Transparent, try a seymour duncan pickup booster. It's not an OD, but the inherent nature of an overdrive (hi, I'm going to clip the shit out of your signal) kinda takes it out of the transparent realm.
A TS9 is far from transparent, but a stock one works well with many amps because it narrows the frequencies a bit (tightens things up). Different amps like different drives, your best bet may be to try several from different friends and see what you like.