I have many projects, but some of them are just short code libraries and snippets that I don’t want to allocate an entire blog post for. For more information on each, visit the link and read the “readme” provided.
LufaUsbAspLoader, a USB bootloader that combines LUFA and USBaspLoader, so it can be used in low-speed USB devices
Arduino-UsiSerial-Library, written mostly for Trinket, works for all ATtiny microcontrollers with a USI
Adafruit-Trinket-USB, a small collection of libraries that enable USB capabilities for Trinket, and other ATtiny V-USB projects