Good idea.
I've been thinking about this also. For now, before we have a technical solution, we could post a note and keep it in our public bookmarks.
Below is the Npub of my account backup #1. I have set my main account to follow my backup account. I will keep the robot avatar for my backup until I use it.
Possible hashtags to find the note:
#Npub
#MyNpub
#MyNostrBackup
#LeoFernevak
#MyNostrLeoFernevak
#MyNostrBackupLeoFernevak
#NpubLeoFernevak
nostr:npub10zc33xkmfem467vpaj53uve4zsaqtdqcpxmvecs0mezt9zg8m80qpem883