Since the transition from Dominions 5 to 6, many of the old YouTubers no longer post as regularly, while a few new channels have appeared.
Regular Dominions content
These YouTubers regularly publish some kind of Dominions 6 content.
itsmu: Lighthearted and well-edited Dominions videos about Mu's multiplayer escapades.
Darkwolf: Bite-sized guides to Dominions concepts.
DarkSideCookies: Casts other player's games and posts his own multiplayer games.
Lucidtactics: Probably the most well-known YouTuber of the Dominions 5 era, Lucid has returned to Dominions 6 recently with his own series as well as casts of other players and the tournament hosted on his Discord server.
Semi-active or inactive Dominions YouTubers
Zan: Known for his "nations at a glance" tutorials and other guides, Zan has several partial playthroughs of Dominions 6 multiplayer games on his channel.
ChazzyBurger: Has a playlist of national overviews and a few singleplayer/multiplayer series. Currently focused on other games.
Babel Builder: Focuses on the singleplayer side of Dominions, having a fairly complete set of national overviews and streamed SP games. Now making videos on other games.