Zubtitle - Zubtitle is an online tool that makes it easy to add captions to any video.
Metastream - Watch streaming media with friends
Streamlabs Podcast Editor - Streamlabs Podcast Editor ― Edit Your Video By Editing Text
Watch2Gether - Watch2Gether is an app that allows multiple people to watch the same content simultaneously and interact with each other while watching.
Kapwing - Collaborative video editor for modern creative teams
StreamParty - StreamParty is a watch communiry, that allows you to watch video streams in sync with the people you care about, on multiple services.