There are 5 repositories under hex-rays-decompiler topic.
IDA Pro plugin which improves work with HexRays decompiler and helps in process of reconstruction structures and classes
Collaborative Reverse Engineering plugin for IDA Pro & Hex-Rays
Hex-Rays microcode plugin for automated simplification of Windows Kernel decompilation.
Python portage of the Microcode Explorer plugin
IDA 7.x VisualStudio 2017 Sample Project for IDA and HexRays plugins (works with Community Edition)
Hex-Rays Decompiler plugin for better code navigation. plugin for IDA Pro.