Kevin Neubauer designed this tiny module that makes it easy to add CircuitPython to a project:

CircuitBrains Deluxe

CircuitPython on an ARM Cortex M4 in almost 1 square inch! This “Just Add Solder” castellated module is perfect for incorporating into your own project. The CircuitBrains Deluxe board footprint is small enough to fit into narrow spaces and wearable projects.

Rolling your own microcontroller board is time consuming. You have to make sure your design has proper power, decoupling, flash storage, and clock. Then you source all of the parts. After that you lay out the PCB and have it fabricated. When the PCB and parts arrive, you have to deal with finicky small-pitch surface mount assembly. Finally, you need to download the sources for the UF2 bootloader and CircuitPython and define your board, compile, and flash. CircuitBrains Deluxe aims to save makers and hackers some time & frustration. Using it in your project is as simple as importing the footprint libraries, adding those libraries to your schematic and layout (along with your USB port of choice), and soldering it on once your board arrives.

Kevin is aiming to launch a Crowd Supply campaign soon:

https://twitter.com/kevinneubauer/status/1231261132041703426