Among the best options for this are Felidar Sovereign with lifegain, Palinchron for infinite mana with Deadeye Navigator, or any of the dozens of combos you can make with Intruder Alarm
If you somehow control a face-down token, you may exile it to activate Primordial Mist's last ability, but you won't be able to cast that token
, , Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle
Consequently, the card prices are higher, especially those from the Big Score epilogue set
The last point I want to make on white is that there are quite a lot of four-drops, and unless youre drafting one that serves a very specific purpose, I would consider costing four a point against drafting a card highly