15. - Arduino AVR Progamming Shield

You can: Burn a bootloader onto a replacement Atmega328 for your UNO. Make a stand-alone Atmega328 breadboard project. Use inexpensive Attiny chips for smaller projects. Reprogram a chip in an existing circuit with an ISP header. This shield lets you: Quickly setup to program chips. Program a variety of chips easily: 8, 14, and 20 pin Attinys. 28 pin Atmega168 or Atmega328. Quickly see if a sketch is working on pin D3. Use on a Arduino Mega (with optional jumpers). Create a stand-alone programmer. https://www.instructables.com/Arduino-AVR-Progamming-Shield/