DxWnd - Windows hooker - intercepts system calls to make fullscreen programs running in a window, to...
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Windowed Borderless Gaming - Play all your games in full screen windowed borderless mode.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Simple Runtime Window Editor (SRWE) - Allows you to pick a running application and manipulate size, position, styles of its main/child windows.
LightShot - The fastest way to take a customizable screenshot.