Enough Nykthos, Shrine to Nyx mana and Kiora, Behemoth Beckoner and you have a really labor intensive infinite combo
Giving creatures the ability to attack or tap on the same turn they enter the battlefield under your control lets you quickly apply pressure to opponents through big stats, attack triggers, and powerful abilities the table would otherwise have a turn to respond to
When he first appeared in Tarkir, players quickly realized he could control nearly every permanent type while being playable in any deck willing to reach eight mana
Five mana to exile most non-land permanents is a lot of mana in an absolute sense, but it could be worthwhile if you are in a color that struggles to find hard removal
In a Two-Headed Giant game, Virtue of Knowledge does not affect triggered abilities of permanents your teammate controls
Heidar, Rimewind Master A 5-mana 3/3 without flying, ward, or vigilance