I2C expanders, or ADCs will give you plenty of pins for whatever project you have in mind. All these require extra components, though. Enter the ExtraCore library for Arduino, a software library ...

The I2C/TWI pins on the Micro are on D2 and D3. For Arduino beginners, these two boards are nearly interchangeable, especially when used in simple circuits like the Arduino's built-in examples.

In case you missed it, the big news is that a minimal Arduino core is up and working ... The ESP’s dedicated I2C pins are on GPIO 21 and 22 for data and clock respectively.