Ive seen plenty of games where Elspeth resolved on an empty board, made three tokens, and slowly buried the table under Soldier swarms
Have him give Captain America some gear for some cross universe synergy
Once hes summoned, you get to amass a five-strong Orc army, and mill five cards to the graveyard, then choose one creature card from that lot to play immediately on the battlefield, with no need to pay the Land cost
Outside of that, Louisoixs Sacrifice could see some experimentation alongside cards like Tamiyo, Inquisitive Student in Commander, but theres very little reason to play this card in constructed since Flare of Denial almost always exists as a superior alternative
With spoilers already underway, there's a lot to unpack