After 3 months pull-requests-rejections-football I managed to squeeze Sitecore to be presented at Awesome List.
What is awesome list?
An awesome list is a list of "awesome things" curated by the community. There are awesome lists about everything from CLI applications to fantasy books. The main repository serves as a curated list of awesome lists, each of them represents the whole world presented in the most friendly way. If you never heard about it, I highly recommend start navigating if from the home page and can guarantee you'll find much great things there.
Until 2020 the list has missed Sitecore, so that I've fixed that. Now the repository contains comprehensive and well classified list of all known GitHub repositories. I personally find it useful for random lookups for certain code for a specific domain upon the demand - that saves much time! But apart from that, it's nice having the whole list of all the open source implementations just to review all the variety of things people did with Sitecore.
Existing categories
As for today, the whole Sitecore repositories are grouped into the below categories. I am leaving the direct links to each of them for the simplicity:
Everyone is welcome contributing to the repo as soon as you got any awesome stuff to add (by PR), but please be aware of the strict guidelines.
Hope you find this list helpful!