Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Nico Nico Douga Downloader - Download anime videos, audio music mp3, thumbnail images, manga from nicovideo.jp
Video DownloadHelper - Browser extension to download videos from the Web
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
StreamFab Downloader All-In-One - StreamFab Downloader All-In-One is a great tool that allows you to download videos from thousands of websites Amazon Prime, Hulu, Disney, HBO, Netflix, amongst others.
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.
GrabAnyMedia - Grab Any Media is a popular video downloading extension for the web browsers.