Marigold, what Slashley and I were referring to were Illuyanka, Horus, and Pazuzu, who are the (up to...) +50% element eidolons. They're actually the next three new, non-collab* advents.

*if we get the Walkure Romanze collab advent after Tiamat, then Mio (the eidolon) is +HP/+double. Then Illuyanka/Horus/Pazuzu come after her, not including reprints. There is enough in between such that Illuyanka is in June, Horus is in August, and Pazuzu is in October.