Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
ReachOut - ReachOut is a field service management suite to streamline field processes with customizable mobile-based forms and workflow.
BuildFire - BuildFire is the easiest way for small businesses to build a mobile app in a matter of minutes for iOS and Android.
DeltaSalesApp - Field Sales Force Automation & Field Force Tracking 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.
Service Cloud Field Service - Service Cloud Field Service is a cloud-based field service solution designed to initiate customer service activities from anywhere.