I had a lot of fun with Riddleform the first time, I am hoping to have fun with it again... Once 3 mana Narset and Teferi rotate out... (but also rip Arclight Phoenix)
A nice trick for Limited to be sure, I'm not so sure about Constructed Izzet spell/tempo decks since you'd usually prefer to cast stuff on your opponent's turn, except for maybe burn spells for that final push against a tapped out rival.
Welcome back, Riddleform. I wonder if this is better in M21 Limited than in Hour of Devastation?
Source: mtg-jp.com
Pioneer:UR Pheonix
Modern:U Mono U Tron
EDH
GB Glissa, the traitor: Army of Cans
UW Dragonlord Ojutai: Dragonlord NOjutai
UWGDerevi, Empyrial Tactician "you cannot fight the storm"
R Zirilan of the claw. The solution to every problem is dragons
UB Etrata, the Silencer Cloning assassination
Peasant cube: Cards I own