Beau Miles - Beau is an Australian adventurer. This channel isn't just limited to running, but adventure challenges in general.
The Ginger Runner - This is how many of us got started in trail running. Ethan and Kim are still producing awesome content, movies, interviews, reviews, etc.
Vo2maxProductions - Sage Canaday, professional ultra trail runner, shares his training tips, nutrition advice, etc.
Billy Yang Films - Billy produces some awesome trail running movies.
Run Steep Get High - Jamil Coury has some awesome content on this channel.
Treadmill TV - Virtual trail running videos to make your treadmill runs more interesting.
Virtual Run TV - Another collection of virtual trail running videos for your treadmill sessions.
Let me know your favourite trail running Youtube channels in the comments. Feel free to plug your own channel.