Things to consider if looking for an ergonomic keyboard (disclaimer: I’m not a doctor): Ergonomic keyboards aren’t cheap, but they’re cheaper than repeating physio visits and months of sick leave. Keep that in mind if you go looking for some.
The following links can be useful for getting a sense of what's out there for ergo keyboards. They're not exhaustive lists, not close, but they can be useful jumping off points.
- Not the prettiest site shows a lot of ergo mice and keyboards http://xahlee.info/kbd/keyboarding.html
- A great comparison site for different split keyboards. It allows one to print the real size on paper, to see how one’s hand would sit on them. Pay particular attention to how the pinkies sit and thumbs sit. You don’t want to reach too far or contort the hand when reaching. https://compare.splitkb.com