Monk’s Cafe is one of my favorites, don’t see that around much. I just bought some at Gerrards Market in Redlands, but that’s a long way from where I usually am.
+1. Especially Sante’s West Ashley, which is quite hard to get. You have to get lucky and be at the brewery when they have bottle releases or trade for it, if you’re into beer trading (I am). The Rare Barrel is great, as well. I’m actually currently drinking Rare Barrel’s Home Sour Home which is practically peach pie in a glass. They don’t distribute either so you have to go to their brewery in Berkeley or sign up for their yearly membership.
I’m also a fan of Firestone Walker’s Barrelworks line of sours. They distribute to stores randomly (You can currently find their Agrestic at a few bottle shops). They always have fun bottle releases though over in Buellton.
If you’re ever in Tillamook, OR, check out De Garde Brewing. They have some of the best fruited sours I have ever had, but, of course not distributed.
Russian River sours will always be classic. I especially love Temptation and Sanctification.
Avery has been putting out a few decent sours lately that are actually distributed. Their Lilikoi Kepolo is very refreshing and perfect for hot weather.
If you’re ever in South Carolina, check out Westbrook Brewing and try their Gose. Salty, sour deliciousness! I often trade for it.