Plus, there's no agreement with what "X" should be
Pongify is the most popular removal spell in blue, and its easy to see why
Corpse Knight Corpse Knight can be a good win condition if you have any sort of repeatable token-creating, blink, or recursion engine
Removal spells Dismember is mostly for creature-based combo decks like Twin and Pod, but its also useful in the mirror, in matchups like Merfolk, and against any random decks that have creatures that will otherwise dominate the board (Im thinking decks that have a couple Baneslayer Angel or something)
Thank You For Being A Friend: Ranking the Ikoria Companions It's always nice when a new set has something for everyone
Mirko, Obsessive Theorist is a 1/3 Vampire Detective with flying and vigilance