I'm just wrapping up a year of maintaining my bullet journal practice using index cards instead of the more popular notebook form factor. It's heavily inspired by the century+ old Memindex method.

AMA

https://boffosocko.com/2023/04/20/review-of-king-jim-a6-size-horizontal-flatty-works-case-5460/

Syndication Link: https://www.reddit.com/r/bulletjournal/comments/15av66m/a_year_of_bullet_journaling_on_index_cards/