Here's a bunch of sites and YouTube channels where you can find useful information about Mythgard:

• The Mythgard Site: Official site of the game, recommend reading their FAQ
• Mythgard Hub: Site for decks and deck building, as well as community written articles and event listings (tournaments and such) for the game.
• The Boneyard: Podcast about Mythgard.
• What's Up Woody: Streamer, has a few very good videos for new players.
• Lore Broker's Files: Videos on the lore of the game.

I'll add more as I find them.