Greasy Fork is available in English.
Online YouTube Downloader v0.7 (MP3, MP4, M4A and WEBM) - Offmp3.app
Alternative to: YouTube Multi Downloader. This script helps to add a download button. Presents the fastest ways to transfer and ensure quality. Supported Services: YouTube, SoundCloud, Mixcloud, Facebook, Bandcamp, Twitter, Dailymotion, Vimeo, Instagram and ReverbNation.