FWIW, a pedal that has taken up permanent residence (at least for now!) in my chain is a DIY build from Aion Electronics called the Lumin Sonic Enhancer. It's a work-alike circuit for the BBE Sonic Stomp, a pedal that had long interested me but which I'd never owned. It's difficult to describe exactly what it does to your signal--I'd say it just seems to make it "step forward" and give it more immediacy, if that makes any sense. I just buy the PCB ($12) from Aion and source the other parts from Mouser and Tayda. Aion even gives you a downloadable Mouser parts list on the product page (which they seem to do for pretty much all their PCB's). But if you're not a DIY'er, you can always go with the original BBE pedal.

Here's a pretty good video of how the circuit works: