For the truly important stuff--financial accounts, home records, insurance, and email--the passwords won't be necessary in the face of a death certificate and executorship. They will be reset and new passwords provided to the executor.
Work passwords for my current job would be... irrelevant. I don't have sole control of access to anything mission-critical and while my work laptop is bitlocker encrypted, the external drive I keep my active case files on is not.
For the unimportant stuff, such as if I wanted someone to be able to access my account here at DSLR for some reason, I have no idea. Such passwords would need to be kept somewhere safe and secure, yet accessible to family and/or friends when needed. I would also need to be able to (and remember to) update the list to account for changes, and that's the sticky part. I suppose a LastPass account would be good for that, since LastPass would certainly turn over the account on proof of death.
Right now I have nothing set up for this. Even when I do, however, the passwords for my encrypted containers... I'm taking those to the grave.
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If only Opera had been open-source...