w2ui - W2UI is a small JavaScript UI library with a complete set of widgets: layout, grid, sidebar, toolbar, tabs, fields, popup, utilities.
HTML5 - 5th major revision of the core language of the World Wide Web
Webix UI - An enterprise JavaScript Library for cross-platform app development with HTML5 JavaScript widgets and easy integration with most popular JavaScript Frameworks.
Angular.io - Angular is a JavaScript web framework for creating single-page web applications. The code is free to use and available as open source. It is further maintained and heavily used by Google and by lots of other developers around the world.
Svelte - Cybernetically enhanced web apps
Blazor - An experimental web UI framework using C#/Razor and HTML, running in the browser via WebAssembly