At the risk of starting something actually useful . . .

What do you control with your feet?
I use a dedicated damper (sustain) pedal connected to its own input.
I use the Korg EC5 foot controller.
Usually it is set up as follows:
A - Vocal Harmonizer on/off
B - Text Down
C - Text Up
D - Intro 1 (to use as an additional break/fill)
E - Break/fill

For some songs, I change it up a bit, sometimes using three of the switches for variation changes.
Occasionally, for special applications, I will set Songbook Next, Variation Up and Down, or Mic presets. Not often for these.
In addition to these, I have one additional programmable footswitch, which I generally leave on multipad start/stop. I'm thinking of assigned a lead sound change to that, probably through a Performance change. Experimenting today.
Oh and when I anticipate using the Chord Sequencer, I have a setup saved for that on the FC5, using the B and C.
I thought it might be interesting to exchange ideas, since there really is no right or wrong, or mine is better than yours involved!