I have had so much fun building out my effects and loopers over the last several years - searching for the sounds I hear in my head, and blending in with all kinds of genres with a little bit of flair. But, if I could only have one pedal, I would 100% choose the Boss VE-20. While this pedal was originally developed for vocalists, the first time I heard it used was by the amazing jazz trumpet player John D'earth. It has a way of capturing wind instruments and transforming them without losing the acoustic quality of the horn.
This pedal is crazy powerful - it's got a 40 second loop, many many built-in style driven effects options, phantom power, delay, reverb and my favorite of all - the harmonizer. Here's an example of that in action: https://www.youtube.com/watch?v=24s21kQ_9k4
On stage, I usually use my flute pick-up (Audix ADX-10) for a clean sound and then connect the Boss VE-20 to a vocal mic (my "effects mic") when I want to engage that. It sort of acts in the way an overdrive pedal would work for a guitarist - it allows me to boost my volume a little (if I'm using the double mic set-up) and adds a little crunch and natural distortion to the sound. I much prefer using a harmonizer to a traditional distortion pedal for this function, I think it suits the timbre of the flute better and also allows more of the natural sound to come through.
I'll be exploring other pedals and electronics in this spot in the coming months, stay tuned and as always, feel free to leave questions and comments!