Golgari wants to Thoughtseize and Fatal Push your early plays, then land Sheoldred and planeswalkers, so Get Lost gives clean answers to Sheoldred, Professor Dellian Fel, and Unholy Annex's Demon token. Beza is a great top-end that stabilizes life against Sheoldred's drain and rebuilds card advantage. Thalia taxes them too but isn't as impactful against a deck full of removal rather than counterspells, and Enduring Innocence is a removal magnet that doesn't do much when they just Fatal Push it. Keep Collected Company and your mana creatures as your core plan since you still want to go over the top on board presence before Sheoldred locks you out.

Izzet Cauldron relies on cheap cantrips and Prismari Charm bounce rather than hard removal, so Clarion Conqueror is excellent, shutting off Reckoner Bankbuster-style activated abilities if they bring those in and presenting a sturdy flying clock. Unlicensed Hearse exiles their graveyard to blunt Eddymurk Crab's cost reduction from instants/sorceries piling up. Thalia is weaker since they're not casting many cheap proactive creatures, and Elspeth is slow against a deck that can bounce your permanents and tempo you out. Keep Collected Company and your full mana base since this matchup comes down to curving out and overwhelming their small permission package.

UBR is full of card draw and reactive instants (Make Disappear, Fiery Impulse), and nearly all of its spells are noncreature, so Thalia's tax stays in and hits hard. Aven Interrupter's flash and exile-target-spell ability is much better here: it can exile their Fable of the Mirror-Breaker or Indomitable Creativity on the stack. The spell becomes plotted, so they can recast it later without paying its mana cost, but Aven makes spells cast from exile cost {2} more. Beza gives a strong late-game body that out-values their card advantage plan and stabilizes against burn from Fiery Impulse. Elspeth comes out because five mana is slow against a deck with efficient removal like Volcanic Spite and counters like Make Disappear and Negate. Two Ouroboroid also come out because a 1/3 dies to Volcanic Spite before it can take over. Eiganjo's channel comes out because they present few attacking or blocking creatures to hit. Keep Skyclave Apparition, which can exile the Fable of the Mirror-Breaker saga itself or The Theorist, Jace Beleren (it can't exile the Goblin Shaman token). Keep Collected Company to rebuild tempo.