Paper wallets, but really just the private keys. That look something like this:
5Kb8kLf9zgWQnogidDA76MzPL6TsZZY36hWXMssSzNydYXYB9KF
But can be made to look like this:
5Kb8kL
f9zgWQno
gidDA7
6MzPL6T
sZZY36hWX
MssSzNyd
YXYB9KF
And practice restoring them, to make sure you know what you are doing.
So, you're suggesting what? Generate a priv key, and write it down rather than printing it on paper?
I always wondered about those split paper wallets you can create too, but never understood exactly how they worked.
No. I export the private key, change the formatting slightly, label it something else like "urine test results from lab", and print it. Then put it in a binder with medical documents.