I only have a few from long long ago (<17 YO). I guess I learned.
1. Scrapping copper out of a transformer and pinched my pinky with a hammer on the edge of the pinky. Kinda split the guts out of the finger. About 1.25" long. Self-repaired. Scars are barely visible.
2. Learned about kick-back the easy way when a chain saw took a bite out of my index finger. You can barely see the scar. Again self-repaired. Scar is barely visible.
3. And not a hand tool one, but it's not fun to play with electricity. I was doing body work on my car (I was 15-16) at the time. Sanding. No shoes. No shirt. Lying on my side. The extension cord was damaged and I caught the damaged part of a flat extension cord between my toes and there was nobody home. I could not let go. So, consciously I screamed. That was enough to distract by body so I could move my leg and let go.
Later in life.
4. Done much later. I was making a custom cutter for a project I was doing on a lathe and I was filing and the file slipped. I cut my finger on cutter.
5. I was working on a roof doing some sattelite work and started to slide. No harness. I said, I know about sliding and static friction. Let me lie down. I stopped sliding.
BTW, there is a table saw that won't cut skin, or hot dogs called the Sawstop.
www.sawstop.com. It puts a charge on the blade and when something conductive touches the blade, the blade is send instantly into an aluminum block. Every occurence will set you back $70 or so, but you'll still have your finger.
I hate the drill and sheet metal, so I try to use pilot bits or bullet bits whenever possible.