Lots of analog tools in this space. Some are
* Bullet Journal - https://bulletjournal.com/
* Getting Things Done - https://gettingthingsdone.com/
* Johnny Decimal - https://johnnydecimal.com/
* Zettelkasten - https://en.m.wikipedia.org/wiki/Zettelkasten
The last I point to Wikipedia, as there are many styles and alternatives of the idea of a "slipbox" and taking notes and the like.
I am partial to Scott Scheper's Antinet Zettelkasten, in the tradition of Niklas Luhmann.
