Appcelerator Titanium - Appcelerator Open Source
MockFlow - A super easy wireframing tool with all the other tools you need in the product design process
React Native - A framework for building native apps with React
Axure - The most powerful way to plan, prototype and hand off to developers, all without code. Download a free trial and see why professionals choose Axure RP 9.
Onsen UI - HTML5 Hybrid Mobile App UI Framework - work with Angular, React, Vue, Meteor & pure JavaScript. Material & Flat design.
UX-App - HTML5 all-in-one mockup & prototyping tool that exports completed interfaces to working HTML + Javascript