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 *and* out, dual Gigabit Ethernet, stereo audio in and out, 4x USB 2.0, 25 reconfigurable I/O)
Great for reference designs, projects, and integrating into new/existing products.
Schematics, layouts, and more available on GitHub: https://github.com/krtkl