Adafruit small 12 8x8 bright square led matrix with i2c backpacks adafruit 1855 these adafruit square yellow led 12in 8x8 matrix displays with i2c save your microcontroller losing all its gpios to multiplexing connecting displays like this can be quite expensive in precious gpio pins but with the added backpack they only use the 2 x i2c signals plus 2 x power connections they are great for microcontrollers with limited outputs such as the adafruit trinkets which only have 5 x io pins