I’ve used TouchOSC with some ESP32 projects I worked on. But since I’m working on the PC anyway I’d just as soon have a Windows OSC client. I downloaded https://openstagecontrol.ammd.net/ but it set off my Avast Malware trigger.
We use OpenStageControl all the time, especially on Linux where there is little else that compares, at least as far as having a configurable GUI goes. I wouldn’t take the malware trigger too seriously, I suspect it is because of all the numerous tiny UDP messages.
For development, Protokol is a great message monitor, but it doesn’t transmit messages.
The JazzMutant Lemur app has a desktop application companion, which can be used even without the app.
OSC/Pilot is a recent (commercial) addition to the OSC family, for Windows, and a great tool - but it is definitely made for actual performance rather than development use, so if all you want is to trigger a few messages while developing its screen real-estate requirements may be too much.
Finally, TWO has a lot of features for creating controllers, recording, editing and playing back OSC messages, but it may be overkill for the purpose of just having a few control widgets on screen, as it is more akin to a DAW.
Ilias of Elk