snickerdoodle can be used as either a standalone prototyping board or combined with a pre-build, auto-detecting baseboard like:

breakyBreaky (0.1" header breakout board)

piSmasher ("SBC" with HDMI in/out, Gigabit Ethernet, USB, 68 reconfigurable I/O)

giggleBits (open-source, hackable Gigabit Ethernet router)

Great for reference designs or for building products.

Schematics, layouts, and more available on GitHub: