The question is inspired by a few comments and a question I have seen recently. The first is a discussion in the 2019 Review post on the subject of research debt; the second a question from johnswentworth asking what people's confusions are about simulacra (which I interpret to be a 'what do you want from this distillation' question).
The question is what it says in the title, but I would like to add that there is no expiration. For example, I recently saw cryogenics back in the posts and questions, which had fallen off the activity radar for years. So old currents of thought are valid candidates, even if the real goal is a re-distillation in light of new developments in the field or all the accumulated communication technique we've considered on LessWrong.
So please describe the current of thought, and your reason for wanting a distillation. The authors may be called to action, or alternatively following Bridgett Kay's suggestion someone else may take up the challenge.