Handlebars.js
Handlebars provides the power necessary to let you build semantic templates effectively with no frustration. An extension to the Mustache templating language created by Chris Wanstrath.
Flux
Application Architecture for Building User Interfaces
Quasar
Quasar Framework
Framework7
Full Featured HTML Framework For Building iOS & Android Apps
Mjml
MJML: the only framework that makes responsive-email easy
Superagent
Ajax with less suck - (and node.js HTTP client to match)
Jade
Jade - robust, elegant, feature rich template engine for nodejs
Mustache.js
Minimal templating with {{mustaches}} in JavaScript
Mithril.js
A Javascript Framework for Building Brilliant Applications
Rx Js
The Reactive Extensions for JavaScript
Lazysizes
High performance and SEO friendly lazy loader for images (responsive and normal), iframes and more, that detects any visibility changes triggered through user interaction, CSS or JavaScript without configuration.
Raven Js
JavaScript client for Sentry
Crypto Js
JavaScript library of crypto standards.
Loopback
LoopBack makes it easy to build modern applications that require complex integrations.
Stimulus
A modest JavaScript framework for the HTML you already have
JSON Editor Online
A web-based tool to view, edit and format JSON
Marko
Marko template engine