Highly accurate I2C RTC, +/-2ppm. Built-in TCXO, backup battery, temperature sensor.
4MB SPI NOR Flash memory. 104MHz, dual/quad SPI, 100,000 write cycles.
32KB I2C EEPROM. Non-volatile storage, up to 8 devices on one bus.
SPI LED matrix driver, controls 64 LEDs or 8x7-segment displays. Daisy-chainable.
16-character 2-row character LCD, HD44780 controller. 16-pin parallel or I2C backpack.
84x48 pixel monochrome LCD, PCD8544 controller, SPI. Nokia phone display.
0.96-inch 128x64 OLED display driver. I2C or SPI, very popular with Arduino.
LoRa 433MHz long-range wireless module, SX1278. Up to 10km range, SPI interface.
GSM/GPRS cellular module. SMS, voice, GPRS via AT commands. Needs SIM card.
2.4GHz wireless transceiver, SPI interface. 2Mbps, 125 channels, 6 data pipes.