I let go of kid #1 for a split second while I was changing his diaper, and he rolled off the bed onto the hardwood floor.
I nipped #2’s finger with the nail clippers. After that, I used an emery board to file nails down.
Worst of all, when #3 was just a couple of months old, a strand of my long hair got wrapped around one of his toes inside his footie sleeper pajamas, and almost cut his toe off. That one resulted in a trip to the ER, because the hair was embedded so deep in that little tiny toe; it took 2 doctors with surgical instruments to fix it. I still feel queasy thinking about it, and he still has a little scar.
Every single time my husband puts a child into a car seat, he manages to bonk the kid’s head on the top of the car. Didn’t matter if it was a car, truck, mini-van, whatever, just BONK every time. Happily, all three are big enough to climb into their car seats on their own, now, and their heads aren’t noticeably dented.