Castor EDC - Castor offers you a user-friendly and fully featured application for electronic data collection.
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Medidata CTMS - Medidata CTMS seamlessly integrates with Medidata Rave to provide real-time views into study progress without manual tracking.
BuildFire - BuildFire is the easiest way for small businesses to build a mobile app in a matter of minutes for iOS and Android.
OpenClinica - OpenClinica is an open source clinical trials software.
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.