Tools / Plugins

CSS

Epic Spinners - Css only. Easy to use. VueJS integration.

Design

Instagram.css - Complete set of Instagram filters in pure CSS

General

Grabient - Beautiful and simple UI for generating web gradients
Scrollama - JS library for scrollytelling
SVGOMG - SVGO's Missing GUI
tlapse - Create a timelapse of your web development... or just automatically take screenshots of your hard work ;)

HTML

amplitudejs - The HTML5 media player for the modern era

Javascript

Array Explorer - Find the array method you need without digging through the docs
Sweet alert - A beautiful replacement for success messages
Sticky Sidebar - a pure JavaScript plugin for making smart and high performance sticky sidebar

SVG

SVG Backgrounds - Bump Set Creative