Basically the same question as for the OP-Z but updated for OP-XY. I’m looking for a portable MIDI controller which is known/expected to work well with OP-XY meeting some requirements:
Kork nanoKontrol / 2 look nice but I don’t have any experience with one of those.
Any thoughts?
I’ve been using an Xkey air (bluetooth LE) and it’s been working pretty well
The Xkey is more like a sleek wireless midi keyboard, while I’m looking for programmable knobs and faders to be able to quickly change parameters (LPF cutoff, reverb, etc) without switching menus all the time.
Actually the Korg nanoKontrol Studio promises to be exactly what I’m looking for (and is close to the only thing you get when you search for anything like this):
Unfortunately this device is likely the worst piece of hardware Korg ever produced. I can ignore the fact that the outdated micro-USB plug can only be half-inserted, the 3-state power switch feels like it belongs to a EUR 2 toy and the software is crap. But it turns off seconds after being activated (for no reason) and can’t be turned back on for minutes then (which seems to be a known issue).
Came across this one, for less than 30 bucks maybe worth a try:
Do any of these generate modulation?
Asking for a friend - can you elaborate on that? What can you do with a midi controller that can do modulation?
Op-XY has extensive midi cc implementation over most things. Being able to modulate more than what the few built-in modulators do opens up a lot of creative possibilities.
Currently I’m considering building my own based on an ESP32. If you have some great ideas let me know, - I’d make it open source anyways but exciting possibilities would greatly improve chances I actually do it 
This one indeed looks quite cute - in Germany it’s for EUR 60, but if it does what it promises it’s fully worth the price IMHO!
Nevertheless I’ll make some experiments with a DIY controller based on ESP32 (like SquidBox but in Python) first.
I see it on AliExpress for 28 EUR (to Austria) but the DIY project surely looks like more fun 
…
In case you also want to program in some more functionality, the latest Neuzeit Drop has some nice tricks for inspiration.
Can you drop a link. Neuzeit does not ring a bell for me yet..
ok, found it, you’re talking about the “Drop” from Neuzeit Instruments https://www.youtube.com/watch?v=BOEOIXWuYTY
for the original OP-1 someone made this for the MIDI LFO effects:
You can imagine a controller that can assign multiple LFO streams (with various shapes like in that app) to any available CC parameters on OP-XY… and there are many:
