A couple forums I love:

 

Djangobooks.com Forum

https://www.djangobooks.com/forum/

Tons of incredible english-language content. Also a great way to meet Gypsy Jazz friends in the United States and abroad.

GYPSYJAZZGUITAR Facebook Group

https://www.facebook.com/groups/116001620450

Great content from the Gypsy Jazz Facebook community

Jazz Guitar Manouche

https://guitarejazzmanouche.com/

French-language forum and community. Great place to find music, information about guitars, and even a guitar marketplace.

Guitars Favino Facebook Group

https://www.facebook.com/groups/283498882674011/

Created by the author of the Favino Book, Patrice Veillon — a wonderful group of Favino enthusiasts, ripe with images of guitars and the old shop.