I'm a huge fan of physical/tactile input (and output) devices. I use foot pedals hooked up to an Arduino for my CTRL/SHIFT/META keys both at work and home, which helps my RSI enormously. I also designed a wearable bluetooth device for adding physical buttons to phones[0] for a school project. I think there's a huge potential for such products, and I'd love to get back to exploring that space at some point.

If you want to get excited about this type of stuff, I highly recommend this TED talk[1].

[0] https://docs.google.com/document/d/1lTOxHxHFjwJXeCLROAPf6OJD...

[1] https://www.ted.com/talks/david_eagleman_can_we_create_new_s...