There are a couple of sizes in 32nds - 17/32s and 25/32s, as I recall. I own them, but don't recall ever having used them. I believe Chevrolet used these sizes on some bolts/cap screws, as part of their policy of making strange engineering decisions (clutch-head screws*, anyone?).
*Actually, the clutch-head screw was/is not a bad design: you can, in a pinch, use a regular screwdriver on it, but a proper clutch-head driver locks in, similarly to how a Torx does. Too bad it never succeeded in the market.