Editors
Screen capture
- OBS Studio - a video capture / streaming...
- Jing - screenshots / screen video capture
- Screencast-o-Matic
- LightShot
- Screen to gif
Online collaboration
- Freehand - online drawing
- ZoomIt - online drawing
- diagrams.net
File managers
Video editing
- Open Shot - a simple video editor
Image viewers
- IrfanView - windows only
Processes & application management
- Process Explorer - windows only