What are some alternatives?
youtube-dl - A small command-line program to download videos from https://alternativeto.
Video DownloadHelper - DownloadHelper is a tool for web content extraction.
Youtube-DLG - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
4k Video Downloader - 4K Video Downloader is a software program that helps people download video files from sites such as Facebook, YouTube and Dailymotion.
ClipGrab - vanbittern entwickelt individuelle Weblösungen.
Freemake Video Downloader - Freemake Video Downloader downloads videos from YouTube & 10,000 more sites. Absolutely FREE. Download YouTube in HD, MP4, MP3. **Voted best of 2018**.