My obsession is Wikipedia lists.
But I also did mention in the post that some of the things on the list are not exactly mysterious. So I'm not sure what the complaint is here.
As for my favorites of the ones that aren't obvious "yup, they died". I like the story of the pirate Henry Every, who made off with a massive treasure that Indian princes had been taking to Mecca for the hajj and then (quite sensibly) divided the loot with the rest of his crew, disbanded said crew, and disappeared. Some of his crew were later caught. A few of them were executed. But most, including Every, apparently just vanished into normal lives. Albeit, wealthy normal lives.
It's not "mysterious" in the "ooooweeeeeoooo paranormal" sense. But it is fascinating and mysterious in the sense of "holy crap a plan like that can actually work!?"