Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Anima App - Design, get feedback, convert to code, publish, iterate.
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.
Timeline for Sketch - Create beautiful timeline animations in Sketch
Bubble.io - Building tech is slow and expensive. Bubble is the most powerful no-code platform for creating digital products.
Monday Hero - Convert design into mobile code 😎