You. Yes, you, the reader of this toot. You are incapable of choosing a secure password on your own.
You object, "what if I"... no, that won't work.
"but"... WRONG
Your brain is predictable.
Randomly generate it. Use dice for the passphrase to your password manager. Individual accounts, randomly generate the passwords with your password manager. Write things down (harm reduction) if you don't want to use a password manager, and use dice to generate individual account passwords.