Mono Red Rally floods the board with small creatures and tokens from Burning-Tree Emissary, Goblin Tomb Raider, and Rally at the Hornburg before pumping for lethal, so a hard sweeper is critical. Drown in Sorrow's -2/-2 wipes their entire token/small-creature board cleanly, and Arms of Hadar does the same, both far better than Suffocating Fumes's weaker -1/-1 which won't reliably kill their 1/1s backed by any pump. Extract a Confession lets them choose the worst creature to sacrifice, which is low-impact against a wide, redundant board, so it's cut for the stronger sweepers. Prioritize deploying sweepers after they've committed multiple creatures but before they can cast Rally at the Hornburg.