The board-du-jour is the diminutive Raspberry Pi Zero. At DEF CON 27, I got to see and hold Pegleg v2 which shrank to a Pi0W (Raspberry Pi Zero W) with a Qi receiver, capacitor, wifi dongle ...
Frustrated with Pi case limitations, a Reddit user created a 3D printable version for cooling. The Cocoanix Case Pro v2 addresses airflow issues and now has GPIO ...