Media.io - Media.io has all the handy tools you need for video & audio converting (.mp4, .mp3, .mov, .mkv, .avi, .wav, etc.) and editing, like generating auto subtitles, applying engaging text, music, effects, templates.
you-tldr - Get the tldr of any YouTube video in seconds
Universal Word - Translate YouTube subtitles into multiple languages
SliceTube - The Fast and Modern way to cut and download YouTube videos
Subtitle Generator - Subtitle Generator will automatically create subtitles for your YouTube videos and translate them into other languages.
GIFit! - Quickly turn YouTube videos into GIFs (chrome extension)