On the left in the videos is Jason Shaw, who after some research I found is one of only three guitarists who have won the National Flatpick Guitar Championship on three occasions (the other is Steve Kaufman). Held annually at the Walnut Valley Festival in Winfield, Kansas for about the last 40 years, it has been won by almost every notable and well known flatpick guitarist, including Tony Rice, Bryan Sutton, David Grier, and Kenny Smith among others. On his right, and sharing leads with Jason is John Shaw, an almost equally accomplished guitarist in his own right. They have a number of videos published, if you like them, just do the usual You Tube drill.
They are not well known outside the Midwest, but perhaps they should be. Both currently play with the Sandy Creek Bluegrass Band.
All you flatpick guitarists should note something unusual about Jason. Unlike the vast majority of bluegrass guitarists, he plays in the Classical position, with the guitar resting on his left leg. You might consider trying this out, as I did, especially if you find yourself experiencing shoulder or other joint pain as a result of your play. The alignment is more natural, and might just work to alleviate the bone, joint, and muscle stress caused by playing. If it does that, it will obviously allow you to become better at what you do. It takes some getting used to at first, but if you stay with it and get comfortable, it's unlikely you'll ever change back.
Oh, and here's another relatively unknown great, Carl Miner, for your viewing and listening pleasure. https://www.youtube.com/watch?v=NLIZ3liWPLs