Kodular - Much more than a modern app creator without coding
Tasker - Tasker is an application for Android which performs Tasks (sets of Actions) based on Contexts...
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Locale - Locale helps content owners and translators work together, so Rails developers are free to write more code
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.
Automate - Automate various tasks on your Android smartphone or tablet.