Leyline of the Void is excellent here. Their Emrakul, the Promised End gets cheaper based on the card types in their graveyard, and Leyline exiles their cards instead of letting them hit it. It also keeps Malevolent Rumble from filling their graveyard (Shifting Woodland's delirium depends on that too). Toxic Deluge and Requiting Hex give you extra cheap, efficient answers to Basking Broodscale and small Eldrazi Spawn tokens, and Toxic Deluge can also sweep Sowing Mycospawn at a higher life cost. Spell Snare is narrow here, since it only catches mana value 2 spells like Basking Broodscale and Malevolent Rumble. Force of Negation can't touch their main creature threats (Emrakul, Sowing Mycospawn, Basking Broodscale) and only hits noncreature spells like Kozilek's Command, Malevolent Rumble and Ancient Stirrings. Keep Fatal Push and Orcish Bowmasters in as premium interaction against their ramp creatures and tokens. Drown in the Loch gets much worse once Leyline is out, because it counts cards in the target's controller's graveyard and Leyline keeps their graveyard empty. It is best on turns before Leyline lands.

Leyline of the Void is devastating against Rakdos Delirium's graveyard-centric plan, shutting down Nethergoyf, Detective's Phoenix bestow recursion, Street Wraith cycling value, and delirium enablers like Stitcher's Supplier milling into the yard. Toxic Deluge is a clean sweeper for their small creatures (Moonshadow once it sheds counters, Nethergoyf, Fear of Missing Out) when they overextend. Force of Negation is less useful since their deck is mostly proactive creatures and burn spells rather than key noncreature spells worth countering on their turn, and Spell Snare only hits a narrow slice of their curve. Keep Fatal Push and Orcish Bowmasters in as efficient, cheap answers to their aggressive low-curve threats.

Consign to Memory stays in the sideboard here. It only counters colorless spells and triggered abilities, and nearly everything that matters in this matchup misses that. Orim's Chant and Silence are white spells, Day's Undoing is a blue sorcery, and Teferi's and Narset's loyalty abilities are activated abilities, so none of them can be hit. Isochron Scepter is the only colorless spell they play, which isn't enough to justify the slots. Mystical Dispute is the better bring-in. It is cheap against their blue core (Teferi, Narset, Jace, Day's Undoing, Consult the Star Charts) and still taxes their white spells at full cost. Spell Snare is weaker here because it only hits mana value 2 and misses Teferi and Narset (mana value 3) and Jace (mana value 4), so trim one copy for the Dispute. Keep Thoughtseize, Force of Negation, and Drown in the Loch as your best proactive and reactive tools against their sweepers and planeswalkers.