Here is a quick list of my favorite YouTube Channels that offer needle felting tutorials.
Sarafina Fiber Art - My favorite needle felt artist! I love her work! Her YouTube channel is awesome and you can learn a lot. Its great for beginner to advanced needle felters.
Felted Sky Studios - Very lovely nature-inspired creations.
Gypsy Felting - From the basics to advanced tutorials.
Living Felt - Mostly flat felting tutorials.
Felt Alive - How to felt people
Fluff-a-Torium - She doesn't have too many videos yet but I love this channel! Mostly wet felting.
Maqaroon - She is great! She does cute kawaii style animals.
Flying Mio - More kawaii. She does tutorials for some of the kits you can buy on Etsy.
Kawaii Felting - She is new to the YouTube scene, but her cute creations are super easy to duplicate, awesome for beginners.
Pufftique - Very cute little creations that are easy to do yourself.
That should keep you busy for awhile! Please let me know of any good ones to add to the list!