The "poor/lazy man" split keyboard with center integrated trackball : r/ Trackballs
Trackball companion for split keyboards
Corne thumb trackball | Custom pc, Keyboard, Hacker world
Keyboard.io trackball? - Typing & Ergonomics - Keyboardio community
This Split Ergonomic Mechanical Keyboard Features a Trackball Mouse - Hackster.io
Logitech ERGO K860 Wireless Ergonomic Keyboard - Grey & ERGO M575 Wireless Trackball Mouse - Easy thumb control, precision and smooth tracking, ergonomic comfort design, for Windows, PC and Mac - Grey :
Adesso 2.4GHz RF Wireless QWERTY Desktop Ergonomic Trackball Keyboard US English | eBay