ATMEGA328P-AU by Microchip: 8-bit RISC CPU, 20 MHz clock, 23 I/O lines. Ideal for industrial applications with SPI, TWI, USART connectivity and low power mode. Features include 2048 RAM bytes, 1024 EEPROM size, and 16384 ROM words.
ULN2803ADWR by Texas Instruments is a peripheral driver with 8 functions, open-collector output characteristics, and built-in transient protections. It operates b/w -40 to 85°C, has a max supply voltage of 3V, and is ideal for buffer or inverter-based applications requiring sink current flow direction.