What are some alternatives?
FlashGot - FlashGot is a browser extension for Mozilla Firefox that is designed to make it easy to download a whole batch of files in one go. The extension is open source and free to use, but it is no longer compatible with the most recent version of Firefox.
youtube-dl - A small command-line program to download videos from https://alternativeto.
Magic Actions for YouTube - Magic Actions is an extension that changes the way you’ll watch videos on YouTube.
4k Video Downloader - 4K Video Downloader is a software program that helps people download video files from sites such as Facebook, YouTube and Dailymotion.
FastestTube - Youtube fastesttube downloader will make your internet expirience faster harder beter stronger.How to merge video and audio .
Video DownloadHelper - DownloadHelper is a tool for web content extraction.