Flinto - The prototyping tool designers have been waiting for.
Siberian CMS - Siberian is an Open-Source and Free App Maker. Unlimited Push Notifications. Unlimited features. Fully Customizable. Download it and build your own app now!
Base UI Sketch Framework - Huge set of everything you need to design and prototype
GoodBarber - GoodBarber is a mobile app creation platform.
Glyphy - Copy & paste fancy fonts + cool symbols ☞✺✐™
Bizness Apps - Create your own app or become a reseller and build apps for others