Here's another one. Perma Grit tools.
They look handy for shaping. You need a good grit when there's CA glue in the way. I have a set of diamond grit jewelers files that I use constantly. The grit is course enough to sand balsa. They were very inexpensive on AliExpress. I didn't think they'd last but I've had them for years.
Here are a couple of homemade tools I use frequently. Ever hear the expression "like a hot knife through butter"? That's how this covering film gadget works. #11 Xacto blade riveted to a 25W soldering iron. It cuts through film without scorching balsa. It does double duty as a super fine trim iron.
These are slotting saws made from stacked fine tooth hacksaw blades. Two blades are 1/16", three make 3/32" etc. Alternate the direction of the saw teeth when stacking the blades. Super glue them together. Heat shrink tubing for a handle. Make some test cuts and grind down the side teeth until the slot cut is exactly the right width.
Jon