Interesting DIYable MIDI note controllers?

Does anyone know of any interesting DIYable MIDI keyboard alternatives?

I’m aware of Le Strum, a sort of ‘omnichord’/autoharp controller.
What about controllers that would be suitable as an isomorphic keyboard?

Any other non-keyboard note controllers?

It is not DIY, but you have an isomorphic keyboard on the Dualo.
I have one, it’s a clever/modern tool !
It integrates also a nice midi looper wich make it easy to make midi loops.
see video tutorials at https://dualo.org/community/videos/#tutorials

It outputs midi (trough its midi or usb conector) on up to 16 midi chanels , depending on the selected midi mode. (see pages 28-30 of the user manual https://dualo.org/support/# )