Great Downloader easy to use can convert into multiple file formats. Fast and impressive
VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
Video DownloadHelper - Browser extension to download videos from the Web
MPV - MPV is an audio and movie player based on MPlayer and mplayer2.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
MPC-HC - MPC-HC, the free, open source media player for Windows. DownloadsNote. Supported Operating Systems: Windows® XP SP3 .
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.