Great Downloader easy to use can convert into multiple file formats. Fast and impressive
MKVToolnix - MKVToolnix is a set of tools to create, alter and inspect Matroska files under Linux, other Unices...
Video DownloadHelper - Browser extension to download videos from the Web
MKVCleaver - MKVcleaver is a GUI (Graphical User Interface) for mkvtoolnix, designed to extract data from MKV...
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
MY MP4BOX GUI - My MP4Box GUI is a Graphical User Interface for the well-known command line tool mp4box.
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.