Passphrase generating command:

look . | grep -E "^[a-z]{4,8}$" | shuf | xargs -n4 | head

Tony Hunt's have I been pwned website:

https://haveibeenpwned.com/

Some password managers that I can recommend:

KeepassXC (offline password manager and fixes issues with KeepassX)

Bitwarden (open source commercial option)

1Password (commercial, but well established and well vetted)