Many years ago I posted a deck titled Library Lockdown, which sought to use global "everybody search for X" effects alongside cards like Aven Mindcensor or Stranglehold to cut your opponent out of the picture. Of course, combining two cards to turn one of those cards from "just okay" to "pretty good" is... well, nice, but maybe not enough to warrant a whole deck. Sure you'll get some strong plays, but your opponent can basically just keep trucking along with his own strategy and maybe come out on top anyway.
The secret, then, is to not just lock your opponent out of symmetrical cards you're playing... lock him out of all cards, forever! Besmirch your foe's search and leave him in the lurch!
The more cutthroat form of this deck uses Opposition Agent, who not only halts an opponent's search efforts but actually hands the results over to you instead! Cutting the drawback off of Ghost Quarter or Path to Exile is plenty strong, but it's not exactly a lockdown. Thus enters the other half of the setup: the deadly Maralen of the Mornsong. On each of your opponent's turns he loses three life and hands you a card of your choice. He may never draw a card again. As long as you have the board under control and keep your life from running out before his does, the victory is slow, cruel and inevitable.
How likely are you to put these two nasty cards together, though? Well, thanks to the Agent lurking around, you can lean into lots of tutoring effects. Scheming Symmetry and Wishclaw Talisman both become insanely good with the threat of taking your opponent's search from him, and can reliably get you either half of the combo either with or without the Agent.
