This Pro Micro 5V 16M Mini Leonardo Microcontroller Development Board For Arduino development board has 4 channel 10 bit ADC, 5 PWM pins, 12 DIO, and a hardware serial connection Rx and Tx you are familiar with Running on 16MHz and 5V, this board will remind you a lot of other Arduino compatible boards that you like.
There is a voltage regulator on board, so it can accept up to 12V DC.
The Micro is a microcontroller board based on the ATmega32U4. It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, an ICSP header, and a reset button.
It contains everything needed to support the microcontroller; simply connect it to a computer with a micro USB cable to get started. It has a form factor that enables it to be easily placed on a breadboard.