Changing my head gasket got me rummaging around in my tool chest more than usual. I'd just bought a replacement 3/8 inch drive 10mm socket to replace one that seemed to have gone missing...then miraculously appeared some time later (I mentioned the loss to a motorcyclist patient one day and he said, "lemme guess...a 10 mm? )
I bought a 1/4 inch drive ratchet a couple years back that was much handier than the 3/8 I'd been using. Also got a wobble extension for the exhaust header bolts. I had a t-driver for a 3/8, but never used it as it didn't seem practical, but started using it...it finally made sense, and the 1/4 inch one I added worked a treat for my project.
I don't have it yet, but decided to pick up the Robot-endorsed long needlenose pliers. We'll see how that works out.
I guess the big discovery is how nice the quarter inch drive stuff works out. As a plus, it's a bit harder to overtighten fasteners.