ESP-12-F Breakout Board
This is a simple plug&play breakout board for ESP-12-F cheap Wi-Fi board (22 pins with SPI, 4 MB flash). The design is small, two-sided, and fits nicely on a breadboard. All 22 pins are available on pin headers. The board includes micro USB port, 3.3 V stabilizer, flash/reset buttons and USB-to-serial converter (CH340G/CH340T). Works well with NodeMCU firmware.
Schematic is based on this design.