As I've mentioned many times before and will again, building a deck has many nuances depending on your commander and how you want to play the game
Building a Control Deck When you build a control deck, your number one priority should be inevitability
Oracle is the huge database of every single Magic card ever produced (bar those struck from the game due to being racist)
You want to amass a lot of elves to pull off the best effects, Windswift Slice, Galadhrim Ambush, and Elven Ambush each get you multiple elves with one card
While Wizards doesn't release hard numbers, some data mining for the recent Theros Gods drop suggested that around 40,000 of the five-drop sets were sold, which seems fairly realistic compared to the sales of some past special products like Mythic Edition , whose sales numbers were public thanks to eBay