6k + 16k + 4k + 25k + 3.5k + 3.2k + 0.3k +21k = 79k < 80k = 64k + 16k ???. I would then suggest to include all of the above options.

How many SAMD21 boards have the external flash? (the itsybitsy and feather boards do I see).

I would think for those SAMD21 boards without WiFi/BLE/.. the framebuffer should be included for basic display of changing info. I use a small I2C OLED for GPS and simple environmental app using a SAMD21 without external Flash for example. I add framebuf to my build which reduces my onboard flash filesystem to 48K.

And sensor processing options (dht, onewire) ... And code(speed) optimizations (Viper, Native) could be useful for lower power MCUs.

I would bias onboard usage towards the compiled C code since the added external Flash gives room for python code.

My 2 cents, if even that.

I made a first package including:

• Set Python feature level to EXTRA_FEATURES instead of CORE_FEATURES.
  EXTRA_FEATURES was needed to enable Viper & Native, but less may be possible. I have to check what exactly is needed.
• Viper and Native code. While on a relatively slow device Viper and Native code is helpful, it might not need all MicroPyton features.
• Support onewire, dht_readinto
• Framebuffer support
• UART flow control