Thanks, hoardofnotions! Yeah, in general this deck typically tries to kill with commander damage as quickly as possible, but has other beats as backup, so Mistfire Adept is good for giving evasion to Shu Yun, the Silent Tempest.

I don't have any Snow-Covered Mountains in this deck because the average price for each version is above $2, and that's the limit for my local budget playgroup. You make a good point about artifact lands, which I had in the deck to synergize with Metallurgic Summonings. I replaced the Seat of the Synod with Faerie Conclave and Great Furnace with Swiftwater Cliffs (often better than Izzet Guildgate). My deck is mostly blue, but I'm keeping all the vivid lands since fixing for a three-color deck can be challenging.

I agree with you on Arcane Denial over Hindering Light. Oona's Grace seems a bit weak, and since I don't think I'll typically have more than 4 cards to exile from my graveyard, I think I'd rather have Plea for Power than Treasure Cruise.

What do you think? And thank you for the recommendations!

I really like Treasure Cruise over Plea for Power. Look at all your 1 and 2 mana instants and sorceries that are hitting the graveyard, those power out treasure cruise super early. Frantic Search could be good too, free spells are good i hear. Fellwar Stone could be good to. untapped mana rock over Coldsteel Heart and there's a good chance at least one of your opponents are running some of your colors.

You make good points about Treasure Cruise, hoardofnotions, but for now I think I'll experiment with Plea for Power and see if I need it faster. Typically I want to have net card gain, so I don't think I need Frantic Search, but I'll keep it in mind. Coldsteel Heart is slower than Fellwar Stone, but Fellwar Stone can't guarantee me Blue mana like Coldsteel Heart can.