One of the reasons I keep my toolbox organized is so I can easily tell if I’m missing a tool. I’ve only lost three tools, but they weren’t anything too important, and two I got for free so it was no real loss. I have found several tools left in cars, however.
I found a 90-degree screwdriver tool in my car. I’d dropped a nut onto the splash shields under the engine, and when I hit them to knock it out, the screwdriver fell out too. I also found a pair of needle-nose pliers under the hood of my car after I bought it.
I found a razor-blade scraper and a utility knife in piles of junk around the shop, and I found the Snap-on tool and Matco screwdriver under the hood of a customer car. I once found a pair of vise-grips clamped onto a tie rod, but I knew based on service history that they were left there by another tech in my shop, so I was able to give them back.