List of Useful Tools

1. BeCyPDFMetaEdit : Tool to edit PDF, Remove password protection. Read More.

2.  Notepad ++ : Tool to edit files, similar to windows note pad with many features.

3. PDFSAM : Tool to split and merge PDF files.

4. Lightscreen: Tool to automate the tedious process of saving and cataloging screenshots, it operates as a hidden background process that is invoked with one (or multiple) hotkeys and then saves a screenshot file to disk according to the user's preferences.

You can download the portable version which doesn't require installation from Here.
 
5. Video Cutter : It is a free video utility to help you to cut and split your video files into small size you can use it as a "video cutter", "video splitter" or "video clipper".

6. Auto Mouse Clicker : A full-fledged autoclicker with two modes of autoclicking, at your dynamic cursor location or at a prespecified location. The maximum amounts of clicked can also be set (or left as infinite).