Scrapbox - A new style of note-taking that lets you create, discuss, and learn together in one self-organizing space.

Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.

Unit Notes for iOS - A simple and powerful note-taking app.

ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...

Doceri - Doceri is a scalable suite of products that allows a teacher or presenter to control a computer's desktop, to control audiovisual technology, and to annotate any presentation in real time with the Apple™ iPad™.

LightShot - The fastest way to take a customizable screenshot.