Just a few blocks of CSS that I've gathered from past projects and some really cool websites around the web.
Feel free to use them on your project, and to add some through pull request.
The best way to add CSS snippets is to create a folder and upload Readme, CSS and HTML files with comment blocks explaining what they should do (also, feel free to add the code to codepen or something like that and provide the link, so users can preview it!).