Is Thoughtcast with multiple creature type requirements that good? Feels like a Ux Fish kind of card, seems unlikely that it should be strong enough to get restricted
The current restricted list has a number of Xerox-ey cards, but I don't think we've ever had a restriction that really hit Fish-type decks more than other archetypes.
Fishlike decks tend to be pretty reactive and metagamey, which makes it hard for them to become really dominant
Monastery mentor comes to mind. It's a human monk that makes non-human monks. Cast just one spell and then each of these becomes U=draw 2. That seems even more bonkers than jeskai mentor already is.
I initially saw this as a worse thoughtcast too, until pyromancer was mentioned. Mentor is strictly superior, but jeskai can run both. Jeskai already runs snapcaster/JVP and dreadhorde arcanist, so that also satisfies this discounting condition. Preordain is better early, but a more cantrippy version could squeeze in 4 of these and just trim a few other spots, going more all-in on a "go wide" kill approach.