Spark File

I don't remember when I first learned about a spark file, but it's been a long time - 2012ish sounds about right:

The Spark File | by Steven Johnson | The Writer’s Room | Medium

The general idea is to write down anything you want to keep, even a piece of an idea, or something that's an incomplete thought. Every once in a while, read through the whole thing and see what your mind finds for dots to connect.