Electrum Bip39 Passphrase. Although it works by using BIP32 strategy you could still import BIP39 seeds into Electrum wallet. Also apart from BIp32 There may be BIP44 Variation which some wallet use to the generation of seeds. The tool will propose numerous choices for the lacking word as well as https://elliottcnylu.wikistatement.com/4420224/the_anatomy_of_a_bip39_phrase_entropy_words_and_protection