Back to the magic school with one deck per college. Five two color decks about spells, counters, auras, sacrifice and the graveyard.
Magecraft triggers whenever you cast or copy an instant or sorcery. It is the Strixhaven mechanic that came back, and it anchors the Izzet and Boros builds.
Increment puts a +1/+1 counter on a creature whenever you cast a spell that cost more mana than that creature current power or toughness. Big spells make the small creature keep up.
A paradigm spell exiles itself after it resolves, then lets you cast a free copy from exile at the beginning of each of your first main phases once you have resolved a spell with that name. One card, repeated every turn.
Opus gives a creature +1/+1 until end of turn whenever you cast an instant or sorcery, and double strike as well if five or more mana went into it. The reward for casting expensive spells rather than cheap ones.
Secrets of Strixhaven returns to the five colleges, and the Commander decks map onto them one for one: Lorehold, Prismari, Quandrix, Silverquill and Witherbloom.
The set spells mechanics reward casting rather than counting cards. Magecraft is back, increment grows a creature whenever a spell outspends it, and paradigm turns one spell into a recurring free copy. Opus points the same direction with a bonus for big spells.
Witherbloom Pestilence is the most reliable straight out of the box. Quandrix Unlimited has the biggest swings if you like casting X spells for absurd numbers.
Quintorius, History Chaser
A Boros graveyard-spirits deck led by Quintorius, History Chaser, discard cards to draw deeper, create 3/2 Spirit tokens whenever cards leave your graveyard, and finish opponents with a planeswalker ultimate that sends your Spirit army in with double strike and vigilance.
Rootha, Mastering the Moment
An Izzet big-spells deck led by Rootha, Mastering the Moment, cast high-mana-value instants and sorceries, create flying Elemental tokens scaled to the spell's cost, and stack extra combat phases to multiply the token attack count.
Zimone, Infinite Analyst
A Simic X-spells deck led by Zimone, Infinite Analyst, stack +1/+1 counters on Zimone to discount X spells, then cast enormous Hydras and Fractals at mana values opponents can't keep pace with.
Killian, Decisive Mentor
An Orzhov auras and politics deck led by Killian, Decisive Mentor, enchant opponents' creatures with auras to goad and tap them, draw cards whenever goaded creatures attack, and leverage 22 Aura effects into a political control engine.
Dina, Essence Brewer
A Golgari aristocrats deck led by Dina, Essence Brewer, sacrifice Pest tokens to draw cards and load counters onto your best creature, gain life through lifelink tokens, and drain opponents with Vito and lifegain payoffs.