I maintain a packet of encrypted data that contains an inventory of all of my data repositories along with the credentials needed to access them. It is kept in a physically separated, secure location. I have designated one person to be, effectively, my executor for these things. They have a cert that allows them to decrypt that data. Their task will be to decrypt the inventory list and determine who gets access to what.

For data that I don't want to survive me, I keep it on a server that has a dead-man's switch mechanism that will erase it if I don't reset the switch regularly.

I also make it a point to minimize the amount of this stuff that has to be dealt with (the dead-man's switch is part of this effort). I have no social media accounts anymore, for instance, so nothing needs to be done for that kind of thing.