$4 DshanMCU Pitaya Lite board comes with MM32 Arm Cortex-M3 microcontroller
DshanMCU Pitaya Lite is an MCU development board based on yet another STM32 alternative: MindMotion MM32 Arm Cortex-M3 microcontroller that is said to be compatible with STM32.
The MCU can be clocked at up to 120 MHz, embeds 128KB SRAM, 512KB flash, and the board offers two USB Type-C ports for USB and DAP debugging, a MicroSD card slot, a few buttons, I/Os are routed via through holes as well as a mini PCIe connector that can be used to connect a display.