Bodily Oddities
143 strange but normal things human bodies can do, each with how many people have it.
Some people can make a low rumble inside their own head by tensing a tiny muscle in the middle ear, roughly 43 to 55 percent of people by the site's estimate. Bodily Oddities collects 143 entries like that, from jamais vu and aphantasia to an extra tendon link between thumb and index finger, and files each one by body region, by kind (trick, reflex, perception, sound, structural variation, rare ability) and by a rarity band that runs from universal to fewer than one in ten thousand.
Tags separate what feels alarming but is harmless from what is worth a doctor's visit, and a Try it tag marks things you can test on yourself right away. The site states plainly that it is not medical advice.