Well any Touchstone site counts since you can auto-recharge their high power trait.
There are a few "power" locations, they are typically found in Adventures. Like there is a forge buried in a castle buried in an Adventure book that gives -5% XP costs to crafting to some such. Only thing I can suggest on that front is start digging in the modules.
Another thing to consider is Node Magic, and even Portals and Dead Magic zones out of FR depending on your tastes. Then of course you have the build-your-owns, the Rashimen stuff, Sanctuary Spell, Forbiddence, the entire point of Permanency, etc. And circumstantial stuff like Frozen Magic that'd obviously benefit having a "home" terrain to play in.