Pixi.js - Fast lightweight 2D library that works across all devices
Humaaans - Mix-&-match illustrations of humans with a design library.
Substance - A JavaScript library for web-based content editing
Control Illustrations - 108 free flat illustrations with customizable characters
Anime.js - Lightweight JavaScript animation library
Ouch! Illustrations by Icons8 - Professional, perfectly matching, and customizable illustrations for any designs