Domain Zoo's engine hinges on Leyline of the Guildpact enabling near-free Leyline Binding, a 5/5 Territorial Kavu, and a Scion of Draco that hands their whole board hexproof and first strike — without the Leyline in play, their deck loses most of its broken draws. The additional Consign to Memory copies are your highest-priority sideboard cards: use them at instant speed to exile Leyline of the Guildpact if it resolves, or to answer Scion of Draco before its static ability locks you out of removal. Flusterstorm and Mystical Dispute upgrade your counter suite to win the Consign to Memory counter-war and stop Teferi from bouncing your threats. Unholy Heat comes out because even with delirium, their primary threats (Territorial Kavu, Scion of Draco) are too large or gain hexproof too quickly for it to be reliable. Lead with Thoughtseize to strip Leyline of the Guildpact pre-combat whenever possible — they play very few ways to recover that enabler from the graveyard.