There's the latest installment of the fic masterlist up at
who_otp - links to pretty much every rare-pairing DW fic on the net. It amuses me that Sarah/Doctor is classed as a rare pairing, but then I remember that ours is but a corner of a bloody massive fandom ;) Most of the Sarah stuff that's up there is either a link to or has been cross-posted here, but there are a few gems I hadn't seen before.
Also, I have to pimp out The Sarah Jane Wardrobe Appreciation Society's
Sarah Jane-O-Matic, which lets you create your own adventure for Sarah, by the handy method of drop down menus.