Eldrazi ramps into colorless threats with explosive mana (Ugin's Labyrinth, Eldrazi Temple, Urza's Saga), so Veil of Summer is mostly weak since the only black spell they cast is Dismember; swap it for extra Nature's Claim to blow up Urza's Saga and its Construct tokens, or an artifact like Vexing Bauble that would counter your zero-mana Pacts. A fourth Pact of Negation helps protect your combo turn from Dismember or Kozilek's Command disruption. Fanatic of Rhonas adds resilient mana acceleration that can come back with eternalize after their removal and helps cast Allosaurus Rider or hardcast threats. Griselbrand and Hooting Mandrills are cut since they're clunky high-cost or delve bodies against a deck that can Dismember or Kozilek's Command your creatures before you combo off.

Rakdos Delirium is a black/red aggro-midrange deck with Thoughtseize and burn, making Veil of Summer live against the black spells but Nature's Claim largely dead since they have few artifact/enchantment targets. Fanatic of Rhonas is a resilient mana creature that survives Lightning Bolt (1/4 toughness) and helps rebuild after discard strips your hand. Dismember answers Orcish Bowmasters or Moonshadow cheaply. Keep one Veil of Summer copy in mind as still useful versus Thoughtseize, but the overall swap favors proactive resilience over anti-artifact tools this deck doesn't need.

Esper Control wants to Teferi, Time Raveler or Narset you off your combo turn and counter your payoffs with Consign to Memory, Spell Snare, and Force of Negation, so Mystical Dispute is excellent since it only costs {U} against their blue spells like Teferi and counterspells. Veil of Summer blanks their Narset/Thoughtseize-style discard interaction and protects your combo from blue countermagic while drawing a card off their blue plays. Nature's Claim has almost no targets here, so it comes out, and a Disciple of Freyalise and the extra Wistfulness copy are the easiest non-land cuts since their enters-the-battlefield value is weakest against a deck full of removal-light countermagic. Keep your full mana base intact and focus on jamming through their tempo plays with protection instead of trying to grind artifacts/enchantments that don't exist in their list.