Great Downloader easy to use can convert into multiple file formats. Fast and impressive
GIF Resizer - Create animated GIFs and resize GIFs too big to tweet!
Video DownloadHelper - Browser extension to download videos from the Web
ConvertOnMac - ConvertOnMac is the best free online converter for every Mac user that supports more than 500 different file formats.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
theonlineconverter.com - Theonlineconverter.com is an online file conversion platform which offers a user-friendly, cross-platform online tools for user's diverse needs. It allows batch conversion of files and is completely free of cost.
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.