In August this year, ergomech.store's hainguyenac teased his RP2040 Bento breakout board. After manufacturing and testing some prototypes, the author shared the source files.
With regards to its footprint, the Bento is resembling the RP2040 Stamp at first sight, but the similarities pretty much end there:
I took the inspiration from the rp2040-stamp. Other than being very similar in footprint, it has little similarities (probably none, not even the pinout). I designed it because I want to offer my keyboard designs with this being the brain, and if I want to do that, I'll have to be able to make my own breakout boards – hainguyenac.
The board doesn't have an onboard USB port, which should be designed as part of the carrier board.
The lack of the USB connector, combined with castellated pads, makes the Bento much thinner than the usual Pro Micro stack.
Features
The Bento is a breakout board with castellated pad to be solder on a carrier board.
The USB port can either be placed on the carrier board or can be used with a breakout USB C board.
The Bento stays flat on the board so it's great for low-profile boards.
Since it can be soldered with castellated pad, it can be used with a PnP machine, allowing mid-scale manufacturing of keyboards.
Resources
The KiCad and Gerber files are available in the GitHub repo (tested with JLCPCB service (coupon) with success):