A very nice discovery for Mac, iPhone and iPad (sorry, Windows/Linux users!): Purelist is one of the neatest note-takers and task managers I've discovered – the only flaw is no folding inside lists (folding does happen elsewhere, but not in notes). It's a minimalist app with a great schedule feature.

The developer promises that folding is on their roadmap (as are tags)!

More details for those interested here: https://purelist.com

Reminds me a bit of Agenda.