This is one of Davie McPhail's most popular videos, though most of his YouTube fly tying tutorials are widely viewed. The work that Mr. McPhail has done is outstanding and I highly recommend his channel.
Kelly Galloup: Zoo Cougar
There is SO much information in this one, even if you don't tie streamers (which you should!). Kelly Galloup is an incredible resource and this video highlights some of his best work.
Parachute Adams, Size 22 with a Twist
Videos from Tim Flagler are recorded professionally, demonstrate quality techniques, and constantly display his creativity. Mr. Flagler's channel is one that you better know if you are a fly tyer!
Wired Stonefly Nymph
Videos by "In the Riffle" are always well done, and this is one of my favorites. The Wired Stonefly Nymph can be difficult to tie, but they sure make it look easy in this fly tying tutorial. Be sure to check out their channel, as the videos are excellent!
Fly Tying: Thomas Harvey's Double Rainbow
Videos from "Fly Fishing the Ozarks" are always fun to watch, as there is lots of music and neat stuff going on! The instructional component may be a little lacking at times, but the materials will always be displayed and you can typically get the gist of the pattern in a short amount of time.
Tying the Clouser Minnow with Bob Clouser
In this video, Mr. Bob Clouser share his famous pattern with all of us!
Rim Chung Ties the RS2 - Short Version
Mr. Rim Chung demonstrates the techniques behind his incredible fly, the RS2.
Marc Petitjean: Parachute Mayfly
This video was posted by "The Weekly Fly," and they have some incredible content on their channel. In this tutorial, Marc Petitjean shows us his skills in working with CDC.
This video came recommended to me, and I know every warmwater fly fisherman will appreciate the pattern!
Mylar Mackerel Crease Fly
This saltwater fly came through a recommendation, and what a fantastic looking pattern!
Parachute Hackle Technique
Mr. Barry Ord Clarke has some great content through his channel, thus be sure to enjoy this video and MANY of the others he puts out there for all of us to learn from.
Tie Like a Pro, Ep. 4 Head Designs, Part 4 - Jig Flies
Lots of information in this one, part of Gunnar Brammer's series, "Tie Like a Pro." Gunnar has some excellent videos on YouTube, and I encourage you to check out more on his channel.