Ergonomic Keyboard for OS Sierra
I know of and can recommend two different ones because I had two employees that, due to medical issues needed these keyboards.  One was a photographer and the other was a programmer.  Both swore by them. 


Goldtouch Ergonomic Keyboard for Mac
Kenisis Freestyle Keyboard 


A simple Internet search yields a number of results.

That said, the Microsoft ergonomic keyboard works just fine under on a Mac.  In fact, I have both the Apple keyboard and a Logitech K380 (Windows) keyboard hooked up simultaneously and both work just fine.

You just have to be aware that the Windows key functions as the Command key.