Lots of people seem to like custom keyboards and programmable HID widgets. Saw this and it seems interesting. Being Adafruit it is commercial on some level but also well documented for replication and mods that are more useful than the average shared project.
https://www.youtube.com/watch?v=A8RW3y0CIgw

YT description:

Build a 3D printed USB chorded keyset inspired by the original Doug Engelbert “Mother of all Demos” keyset from the 1960’s. This 5-finger keyset lets you type without moving your hand, entering full words and phrases by pressing multiple keys simultaneously as a chord. Read more link below

Learn Guide https://learn.adafruit.com/usb-keyset

USB Keyset Learn Guide: https://learn.adafruit.com/usb-keyset/