A 5-mana Elder Dragon from Secrets of Strixhaven with flying haste that gives every instant and sorcery in hand miracle {2} — and taxes opponents' upkeeps into a loot engine on top.
Spellslinger decks. Every instant and sorcery in hand becomes a two-mana miracle the moment it's drawn first in a turn, which is a huge discount on an expensive spell.
Card-selection engines. The repeated loot trigger on every opponent's upkeep is a real way to dig toward the best spell to miracle out, on top of simply filtering the hand.
Aggressive Boros tempo. Flying haste means it applies pressure the turn it's cast, on top of whatever card-selection value it generates afterward.
How it does in Commander
As the commander
As the commander it rewards a spellslinger deck built around a hand of instants and sorceries specifically, since guaranteed access to the effect from the command zone turns every relevant spell drawn first in a turn into a potential bargain.
In the 99
A strong include in any Boros spells-matter deck even without leading it, doing real work both as an evasive threat and as a card-advantage engine.
Formats it's strong in
Spellslinger decks. The miracle discount rewards a deck already running a hand full of instants and sorceries, which is exactly the plan those decks want anyway.
Decks with expensive top-end spells. The bigger the spell being drawn first, the bigger the discount from miracle {2} relative to its normal cost.
Formats it's weak in
Creature-heavy or low-spell-count decks. With few instants and sorceries in hand, the miracle effect has little to work with.
Decks that dislike discarding. The upkeep trigger requires a discard to draw, which is a real cost for a deck with a tight, carefully sequenced hand.
Synergistic cards
Cyclonic Rift — A classic expensive instant that becomes an enormous discount the moment it's drawn first under the miracle effect.
Fireball — A scalable X spell that's still strong even cast for two mana under miracle, if drawn at the right moment.
Faithless Looting — Stacks its own looting with the repeated upkeep trigger to dig even faster toward the best miracle target.
As a recent-set card, Lorehold, the Historian is affordable and a reasonable pickup for a Boros spellslinger deck — low financial risk for a genuine engine.