A list of the 4 libraries in the architecture atmelavr.

avdweb_VirtualDelay Allows using (multiple) delays without blocking code execution. Arduino Uno and Zero.
Mcp3208 Arduino library for the MCP3208/3204 12 bit ADC.
PJON PJON is an open-source, multi-master, multi-media bus network protocol
TinySnore Library for putting ATtiny25/45/85 to timed sleep in one line of code!