I can think of two that haven't been mentioned:
1. Helping break up sediment in a cat's urinary tract. Put some apple cider vinegar in some wet food or soak it into his kibble. It fixed our cat who had a 90% blockage. Good to go 2 days later. To be fair he also had a muscle relaxer from the vet, but I doubt that did any good for him other than dope him up a bit...
2. Heartburn treatment: It turns out that some people get heartburn from TOO LITTLE stomach acid. Taking tums and other antacids just make it worse. My wife's doctor had her start drinking a very weak vinegar solution in the mornings and it really helped. It's to the point now where she doesn't need it at all, but her diet has changed drastically since then, but it did help at the time.
I can also attest to the fact that white vinegar WILL remove rust. I had a big box of old rusty gun parts that I put in a tub of vinegar. 48 hours later they were clean as a whistle.