Tom Collins created an incredibly effective and free YouTube resource, Banjo Blitz, that was the primary ingredient in my learning clawhammer banjo. If you're new to clawhammer, in my opinion, this is where to start. Join Tom's Patreon community, Banjo Quest, for more information. While there are many other great online resources, Tom's module-based platform is simply the one that resonated most with me. Tom is also an incredible player and teacher, and everyone should buy his album "Sinful to Flirt" to hear killer banjo and fiddle. He is heavily inspired by Round Peak clawhammer.
I also have really enjoyed watching and listening to Clifton Hicks, an index-lead, three-finger-style player heavily influenced by George Gibson. Clifton's wild playing and vocals are gripping, and his Patreon provides excellent learning content (both playing and historical) as well. I've included below two of Clifton's videos but please go to his Patreon account for the whole story. And to support him.
Also, a fellow named Cameron DeWhitt runs a blog called "Get Up in the Cool" -- see more details here. Learn who's who in this world by listening to all his old podcasts. He does a good job and had been able to get some great guests.
For those interested in learning to build an open-backed banjo, I'd recommend the following:
(2) www.banjocraft.com. These folks also published a book, much of which is available on their website. Both the book and the website are solid resources.
There are many resources and ways to get connected with this strange group of folks -- far more than I can list. But here are a few:
Facebook groups include "Clawhammer Rules" and the cleverly-named "Clawhammer Banjo."
If you're on Instagram, start following a few of these hashtags: #dropthumbsnotbombs #clawhammerbanjo #openbackbanjo
And then there's www.banjohangout.org. The amount of content here is mind boggling. Join, converse, ask stupid questions. There are forums for it all.