maim - maim (Make IMage) is a spiritual successor to scrot — a simplistic CLI-friendly screenshot tool.
Gnome Screenshot - GNOME Screenshot is a utility used in the GNOME desktop environment for taking screenshots.
Flameshot - Powerful yet simple to use screenshot software for Linux.
Snagit - Screen Capture Software for Windows and Mac
Snipping Tool - Use Snipping Tool to capture a screen shot, or snip, of any object on your screen, and then annotate, save, or share the image
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.