Bip39 backup https://500px.com/p/alexzhiglatyxrnxb While it takes advantage of BIP32 strategy you may still import BIP39 seeds into Electrum wallet. Also apart from BIp32 There's BIP44 version which some wallet use to the era of seeds. BitBox02 - A successor for the BitBox sequence, this hardware wallet supports BIP39 seed phrases https://pixabay.com/users/51089543/