Being a tinkerer, my wife often tries to surprise me with tools for gifts. Last Christmas she bought what has become my #1 favorite tool to use when working at the 4×8 CNC router.
This nifty Rockwell Sonicrafter multitool is great for lots of oddball jobs where other tools fail.
For CNC router cuts, I work without a vacuum table so almost all of my parts have tabs to hold them in place while the bot finishes my cuts. Armed with a small cut-off blade, this tool has found a permanent home plugged in next to the ShopBot where it is at the ready to cut through the tabs on all of my work. You can flush cut right up to your finished part without having to wrestle a sheet of sliced up plywood hanging off the end of your table.