It might not seem too impressive these days, but when microcontrollers with hardware USB support were more expensive and rare, the VUSB library was often used to create USB devices with an ATtiny85.

A custom PCB clone of the Digispark development board — a minimal ATtiny85-based microcontroller board with native USB programming support. Designed from scratch in KiCad. The original Digispark is a ...

The original Digispark is a tiny Arduino-compatible board built around the ATtiny85. This is a custom PCB recreation of that design, including the USB low-speed interface circuit for programming ...

Sure, countless microcontroller development boards featuring a USB connection have made it to the Projects and Tutorials pages of Electroschematics. Although these days it really is easy to build your ...