ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Roboflow Annotate - Annotate images with ease. Export to any format.
Thum.io - A real-time website screenshot generator
Annotable - Ultimate image annotation & markup tool
Blink - Blink is a team and employee app, with a Feed, Chat and Hub (for documents, links, files).
Annotate Screen - Browser based annotation tool.