Historic Niv-Mizzet by Charizard James
As much as it makes sense to play a lot of cheap one-for-one effects in a deck where Niv-Mizzet Reborn can get you big card advantage later, discard is just very poorly positioned in a format dominated by Brainstorm.
In addition to that, I felt like I only had Niv and one Hydroid Krasis as big cards and if I didn’t draw them or if they kept getting countered by my opponent’s cheap permission spells like Memory Lapse, Mystical Dispute or Aether Gust, I wasn’t really doing much.
I mentioned that I wanted to take a closer look at the deck, cut the discard, add Growth Spiral and more cards that can draw me some cards and just rebuild the deck.
Before I even got to do that, I came across this list from Charizard James which looks very close to what I wanted to do. Growth Spiral should help you double-spell faster and Prismari Command is another card that lets you play Niv on turn four thanks to a Treasure!
I still want to have more copies of Hydroid Krasis in the 75 though because Niv is just so easy to counter, whereas Hydroid’s ability will always get you the extra cards and if they keep Memory Lapsing or Gusting it, you’ll always come out ahead.