For most on the go situations, I rely on my Korg GT-3 or either a Boss TU-12, to carry on the gig bag's pocket and use as needed. And I have not had bad results with those. However... on my rack rig there is this Behringer (BTR2000 if I'm not wrong) that works quite well. Dual inputs plus mic, a slant edge with LED lights that allows me to use it as a rack lighting unit (put on the top rack space), it also serves as a metronome (with both sound and a swing-motion Led line, not that I use it live, but useful for studying at home), and makes no noise when used in-line (I feed it with a dry output of a Digitech RDS1900 DDL I have on my preamp's FX loop).
On my main guitar rig, however, I use a control pedalboard (Roland FC100 for controlling a GP-8 centered rack system) and was needing a tuner I could hook on the floor to the tuner output of the FC100 and was having a hard time finding an accurate and BIG one I could see without my eyeglasses on -I have a tendency to sweat profusely on stage, and lately have been preferring to perform without them-, and after trying quite several units, I've found the Morley Accu-Tuner stomp unit the best choice. I can see it in sunlight situations, the LED is BIG, I can see big letters and either standard arc-type or strobe tuner-like indicators. I have used only once with a bass, but either way I've found the response is good.
My humble 0.02