Note to self: Add cards like Widespread Panic to the list.

Psychic Surgery works for top of deck tutors.

xQubit, true, but I think even punishing a tutor by controlling the next draw could be good. Thanks!

Great list, thank you for making it! Would Cosi's Trickster fit in here?

brewtzar, thank you and you're welcome! Cosi's Trickster benefits off of opponents tutoring, but the effect is just too small to really matter. For example, having a big creature with no way to evade blockers isn't too much of a threat in comparison to someone tutoring for combo pieces or answers.

You need to add the new Ashiok!

eskanonen, done! :)

Shadow of doubt also fits the bill. It could be recurred in the right deck or could just be used to stop a specific tutor effect.