@M'vy For user-chosen free passwords, a simple trick to slow down thieves might be to use a common prefx or suffix for each password not written in the notebook. Initiatives like the
Password card also seem tempting (it goes along with your seeded idea I think), albeit more complex to use, otherwise for people who do not want to handle the protection of their password manager there are online services (whether browser's sync feature or services like LastPass).