Theater of Horrors targets its own library and removes a card at the beginning of the upkeep, which can be played if an opponent has lost life points
Personally speaking, the second option to flicker a nonland permanent is the best ability among the three
Thats especially handy because Flynn Rider, Charming Rogue can be surprisingly painful to get rid of as an opponent
The bigger and nastier your foes become, the biggest and nastier Dong Zhou works to dial them back
Deputy removes virtually anything in the early game that's going to cause you headaches like Conclave Tribunal, Search for Azcanta, and any other creature you'd like to assume room temperature
Our mana rocks like Astral Cornucopia, Everflowing Chalice, Empowered Autogenerator, Mindsplice Apparatus all generate more mana as we proliferate, our storage lands like Dreadship Reef also become huge rituals, Vat of Rebirth and Lux Cannon get way more effective, we can speedrun through sagas like Phyrexian Scriptures and so much more