Blue Pill Breakout/I2C Hub PCB Only from Land Boards, LLC on Tindie
Amazon.com: [initeq] STM32 ARM STM32F103C8T6 Blue Pill Minimum System Development Board with ST-Link V2 USB Programmer (1-Pack + ST-Link V2) : Electronics
Blue Pill Vs Black Pill: Transitioning From STM32F103 To STM32F411 | Hackaday