@peertube is the Fediverse's video sharing network. You can follow and interact with PeerTube accounts from Mastodon.
For example, you can follow @theatticdwellers and when they publish a new video it will appear in your Mastodon feed. If you like one of their posts, that will show as a thumbs up on PeerTube, and if you reply to a post it will show as a comment under the video on PeerTube.
More info about all of this (and also how to publish your own videos) at:
@feditips @peertube @theatticdwellers any idea what the most popular peertube channels are?
@cubeofcheese @peertube @theatticdwellers
The most popular in terms of followers are probably @thelinuxexperiment and @blender
But if you're looking for interesting content I have an account at @FediVideo which boosts good videos from PeerTube, even if they're from small channels.