Largest collection of navel fluff
In terms of rare collections, this one gets top marks. An Australian librarian has made a habit of collecting his naval lint. He started “harvesting†his fluff in 1984, at a youth hostel in Brisbane. After 26 years, the complete collection now weighs 22.1 grams, or .77 ounces.
And I collect a list of things I don't need to collect. It's huge.