Norme bip39 https://list.ly/i/11078004 While it utilizes BIP32 approach you could continue to import BIP39 seeds into Electrum wallet. Also besides BIp32 There is certainly BIP44 Variation which some wallet use for that era of seeds. It's very simple — if you don't worry about copyright inheritance, nobody else will — https://agendabookmarks.com/story20125510/bip39-online-generator-bip39-npm-no-further-a-mystery-https-dzen-ru-bip39-phrase-com