Besides the obvious ones like level, gain, rate, depth, and mix for various effects:
1. Intelligent Harmony notes to change intervals on the fly. For example, assign the pedal to the Voice 1 Harmony parameter and set min to +3 and max to +4 in the modifier. Heel down would be a third up harmony (major or minor depends on key and scale chosen) and toe down would be a perfect fourth up. Lets you create more complex harmony passages on the fly by rocking the pedal back or forth for certain notes. Set max to +5 and you'd get three choices. Heel down is still a third, half way would be a fourth, and toe down would be a fifth. You will get discrete steps for each interval, not a smooth bend like with the whammy. Use the Glide Time parameter to set how quickly the chosen intervals transition from one to the next. Set the Glide Time a bit higher for slower pedal steel type harmony bends between intervals.
2. Manual filter sweeps. Similar to wah (a type of band pass or peaking filter) but with any filter type (high pass, low pass, notch, band pass, peaking, whatever). You can even layer multiple filter sweeps (series or parallel) and have them sweep in different directions if you want for some crazy synth style filter sweep sounds.
3. Delay Runaway. Recreate the craziness of analog delay pedal oscillations without bending over to fiddle with pedal knobs. Assign a pedal to the delay mix, feedback, and time parameters (all three to the same pedal). Use the modifier settings for each to overlap and control their individual responses. Basically you want heel down (Min modifier settings) to be normal settings for all three so you can play normally. Set the mix and feedback curves so they ramp up high quickly, pushing the delay into oscillation. Set the time curve so it ramps up later in the pedal travel so you can get oscillation before changing the pitch. Set the max time above the chosen min setting to make it pitch bend down or set it below to make it bend up as you move to toe down. Somewhere in the 10:1 range works pretty well. The wider the time change range and the faster you sweep the pedal, the more it bends the pitch. Sweeping the pedal back to heel down will make the oscillation die down and go back to normal delays. It takes a little trial and error to get the modifiers all setup right, but it's fun to fart around with. You might also want to put a compressor block setup as a limiter (ratio and threshold both set very high) after the delay block too keep the delay oscillation level from getting too high and making things clip.
Calibrate the other expression pedals on the MFC-101 or whatever MIDI controller you are using. The Axe II pedal calibration is only for expression pedals connected directly to the back of the unit (MK1 and MK2 support one pedal and the XL and XL+ support two pedals).
(some amps require decreasing level too on the inverse slope to manage SPLs - haven't figured out why some do and some don't (MV types?) Love this, but can also do it w Scene controllers.
