A list of brothers I can come up with looking through the players who have played with Canterbury include:
Col & Kevin Brown
Ken & Neville Charlton
Tony & Phillip Charlton
Clive, Ray, Jim & Keith Gartner
Steve & Paul Gearin (& Greg)
Simon & Ben Gillies (& Duncan)
Kevin & Col Goldspink
Luke & Bryson Goodwin
Garry, Graeme, Mark & Chris * Hughes
Corey, Glen & Steven Hughes
Brett & Shaun Lane
Ewan & Jason McGrady
Brett & Josh Morris
Steve, Chris, Peter Mortimer (& Glen)
Sam & Lloyd Perrett
Gerard & Ron Raper
Terry & Barry Reynolds
Matthew & Mark Ryan
Darren & Jason Smith
Bill & Frank Sponberg
Brian & Ron Thornton