DroidCam - DroidCam – Use your Android phone as a wireless webcam or an IP Cam!
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Iriun Webcam - Use your phone's camera as a wireless webcam in your PC or Mac.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
iVCam - iVCam transforms your Mobile Phone / Pad into a webcam for Windows PC.
LightShot - The fastest way to take a customizable screenshot.