Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Video DownloadHelper - Browser extension to download videos from the Web
HandBrake - HandBrake allows users to easily convert video files into a wide variety of different formats.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
dmMediaConverter - FFmpeg GUI
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.
Format Factory - Format Factory is software that allows the user to convert media into various file formats. The software is a product of PC Free Time, a Chinese software development company. Read more about Format Factory.