Animista - is a place where you can play with a collection of ready to use CSS animations, tweak them and download only those you will actually use.

Cachex - a powerful caching library for Elixir with support for transactions, fallbacks and expirations

retext is an ecosystem of plug-ins for processing natural language.

Staticman - handles user-generated content for you and transforms it into data files that sit in your GitHub repository, along with the rest of your content.

Best Practices for Building a Microservice Architecture. Looks like a wide set of questions covered.