Tracery : A story-grammar generation library for javascript. Write grammar objects, get generative stories.
Photon : UI toolkit for building desktop apps with Electron.
Prototype : Easy Ajax and DOM manipulation for dynamic web applications
TraceKit : Not all browsers support stack traces on error objects, but TraceKit squeezes out as much useful information as possible and normalizes it.
Bespoke.js : Bespoke.js is a super minimal, modular presentation library for modern browsers, designed to foster a rich plugin ecosystem.
Namespace.js is a small javascript script which provide namespacing utilities. It is framework independent. It also allows you to remotely include files.