1. Arduino Uno: The Arduino Uno is the most popular and widely used Arduino board. It has 14 digital input/output pins, 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button.
2. Arduino Nano: The Arduino Nano is a small, complete, and breadboard-friendly board based on the ATmega328. It has 14 digital input/output pins, 8 analog inputs, a USB connection, a power jack, an ICSP header, and a reset button.
3. Arduino Mega: The Arduino Mega is a microcontroller board based on the ATmega2560. It has 54 digital input/output pins, 16 analog inputs, a USB connection, a power jack, an ICSP header, and a reset button.
4. Arduino Due: The Arduino Due is the first Arduino board based on a 32-bit ARM core microcontroller. It has 54 digital input/output pins, 12 analog inputs, a USB connection, a power jack, an ICSP header, and a reset button.
5. Arduino Mini: The Arduino Mini is a small microcontroller board based on the ATmega328. It has 8 digital input/output pins, 6 analog inputs, a USB connection, a power jack, an ICSP header, and a reset button.