Niv Mizzet control deck. Mostly an Izzet deck, white most importantly gives access to board-sweepers so we don't die to every aggro deck we see. Teferi is a nice bonus, but the main goal of the deck is untapping with Niv-Mizzet.
The deck is played almost entirely at instant speed, exceptions being the win-cons, Search for Azcanta, and Deafening Clarion. Crackling Drake is a good alternate win-con because of how huge he can get in a long game, and he's sometimes easier to protect than Niv. Plus, it doesn't die to Deafening Clarion, so it can take advantage of the lifelink mode. The deck currently struggles game one against aggro, and has no answers to Carnage Tyrant in the main deck. Lyra Dawnbringer can race Carnage Tyrant, and Detection Towers get around its Hexproof. Niv-Mizzet eats control decks alive, bringing us more value the harder they try to remove him.
Siren Stormtamers in the sideboard because of their flexibility--in many games a 1/1 flier isn't enough pressure, but the one-mana counterspell they bring can help protect Niv in the late game, plus it counters Thought Erasures and Settle the Wreckage.
Blink of an Eye in the sideboard because the card is also very flexible. It protects Niv, can sometimes act as a combat trick or a 2-for-1 if our opponent tries to enchant something, it can reset Teferi, and can help clean up things that we failed to counter and cannot kill (like non-creature permanents).
Lyra Dawnbringer and Detection Tower are there specifically for decks with Carnage Tyrant. The Tower hoses its hexproof, and Lyra can race it in the air.
Settle the Wreckage is good against aggro of course, a few more in the sideboard in case we absolutely must draw a board-sweep to win. Lava Coil is also good if the opponent has a large number of creatures.
Opt and Shock are in the maybeboard because I'm unsure how well they perform compared to Radical Idea and Lightning Strike. Might go two and two for both depending on the meta. Banefire is also a maybe because it's a good closer against control, but this deck already performs so well against control that I feel its better to cover our other matchups. Expansion / Explosion is also a maybe because I often have difficulty finding time to cast it, and its purposes are largely served by other cards in the deck. Casting Explosion for X = 4 in the late game is sweet, but a number of Chemister's Insights covers card-draw, and dealing damage to our opponent is inconsequential until one of our win-cons is on the board. It doubles as removal, sure, but it's too expensive to be reliable. I'd rather not blow 5 mana to kill a 1-drop, and I won't likely have 12 mana open to kill a Doom Whisperer before it kills me.
