Felsina is good and Castell’in Villa probably even more so.
Some of my biggest favorites are Fattoria Poggerino and Val delle Corti - both very fresh, serious and structure-driven wines. Both make terrific CC and bangin’ CCR. This was also the reason why I wanted to visit the wineries on our vacation a year ago.
Candialle also makes wonderfully fresh and vibrant wines - I love both their lighter, more easy-drinking CC La Misse and their more serious and structured CC Candialle.
And of course Montevertine’s wines are superb, even if they choose not to label them as CC!