Servoy is a cross platform RAD development and deployment environment for large business apps. Its mostly used by ISVs and enterprises.
Community, training and support specifically for freelancers
Simple and flexible HTML, CSS, and JS for popular UI components and interactions
Ionic is a cross-platform mobile development stack for building performant apps on all platforms with open web technologies.
A modern responsive front-end framework based on Material Design
A UI Component library implemented using a set of specifications designed around natural language
The most advanced responsive front-end framework in the world
A framework for building native apps with React
Angular Material is both a UI Component framework and a reference implementation of Google's Material Design Specification.