Mostly vscode.
1 folder per ticket (epic/issue/task), multiple files per folder. Folders can be nested if needed.
Files: markdown for notes, Todo+[1] for todos, plantuml for diagrams, etc
I also use pen and paper for scribbling.
Scott explains the current state, the problems, and the possible solutions of the copyright laws really well. This definitely gives me a new perspective behind all those "copyright claim" headline news.
[1]: https://marketplace.visualstudio.com/items?itemName=fabiospa...