Kahoot! - Kahoot! makes it easy to create, play and share fun learning games in minutes—for any subject, in any language, on any device.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Mentimeter - a web-based polling tool for workshops, conferences & events
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Sli.do - Slido is the ultimate Q&A and polling platform for live and virtual meetings and events. It offers interactive Q&A, live polls and insights about your audience.
LightShot - The fastest way to take a customizable screenshot.