Great Downloader easy to use can convert into multiple file formats. Fast and impressive
errProof - The website has a lot of useful and unique tools.
Video DownloadHelper - Browser extension to download videos from the Web
Getcalc - getcalc.com - online calculators, formulas & work with steps (step by step calculation) for expressions, statistics, probability, finance, health, geometry, general purpose & engineering calculations along with basic & scientific calculators.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
Insect - High precision scientific calculator with full support for physical units.
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.