Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
BuildFire - BuildFire is the easiest way for small businesses to build a mobile app in a matter of minutes for iOS and Android.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
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.
LightShot - The fastest way to take a customizable screenshot.