No, that would need a completely new mnemonic system. There are some userscripts that give other mnemonics, but some of them don’t work well anymore (KanjiDamage mnemonics, community mnemonics).
To tell similar kanji apart, the best way i’ve found is to just follow WK’s teaching method and look at the individual radicals, and make a (unique) story out of them. It’s a big difference whether it’s tsunami stand (WaniKani / Kanji / 泣) or rice stand (WaniKani / Kanji / 粒). Either you stand there crying a river (tsunami), or you stand in a field of grains. For example. And if you don’t want to use such a system, you’ll just get used to telling similar kanji apart over time anyways.