M5Stack - stackabled development boards, which be useful for your development. This is description of M5Stack project in one sentence.

The main advantages of M5Stack are Arduino IDE library, whole project is opensource and M5Stack supports LCD.

The device contains one main board, now is it ESP8266, LoRa modul and 2" LCD.
You can buy a lot of boards to Core. For example wave generator and logic analyzer, board with temperature/humidity/light sensors and more.

The developers shared tweet about new/another Core on twitter. Now, there is the surprise. The new board will contain ESP32.

So, the latest M5Stack board includes ESP32 with 3D antenna, TF card slot, 2x15 pin header, on-board 1W speaker and 2A IC for charging of batteries. You can use USB TYPE-C, 2" LCD module with 320x240 resolution, reset button and connetor for another I2C devices.

Home webpage of project: http://www.m5stack.com/Home/

Github: https://github.com/m5stack