Bip39 Seed. The passphrase just isn't chosen through the predefined list of 2048 words – it may be any word or phrase you end up picking. What constitutes a "excellent wallet" is one that has very clear, simple to access documentation on supported BIP requirements, derivation paths, and recovery procedures. https://gogogobookmarks.com/story19070841/bip39-wallets-https-linktr-ee-bip39-a-review-of-bip39-generator