Ernst Jünger extensively used card indexes. Among others, he had one, in which he collected "last words" of famous and not so famous people.
He also collected words that are synonymous with or similar to "hand."
Weird ... but perhaps no weirder than collecting passages about fog, as Umberto Eco did. They end up in one of his novels, where he conceives of a character that collects them. Paul Celan collected words in different language for "Herbstzeitlose," and many other authors just collected "beautiful passages."
There are collections that are even stranger (and more difficult to store).