The RP2040-Zero is a tiny RP2040 based controller with USB-C and 20(+9) GPIO pins.
KBD.news Published December 11, 2021
I wasn't aware of this controller until m.ki aka @0002ozlet mentioned it in a tweet about the cool836, a (closed source?) family of 30% keyboards with Alice like layouts.
It's still difficult to evaluate because I only used it for one of my keyboards, but it may be good because it is easier to handle than a Raspberry Pi Pico or Pro Micro thanks to its small size – m.ki.
Published on Sat 11th Dec 2021. Featured in KBD #56 (source).
Seeed Studio is running a sponsorship campaign of the Seeed Fusion Assembly service offering free PCB prototypes for DIY keyboard projects with a XIAO RP2040 controller included.