Some cards will allow you to tap to loot (draw then discard), others rummage (discard then draw), and there are plenty of options out there that allow you to pay mana, tap, and draw a card, too
Once they take control of the game, they can use their evasive creatures as a kill condition
As a result, Aether Revolt will be one of the most interesting sets in years because it will contain not one but two card types (here, I'm counting energy as a card type, even though that's not technically correct) that are dangerous, and Wizards likely felt some amount of pressure to "top" Kaladesh with Aether Revolt
Normally though, we have a clear idea of what the top few spots should look like
When I saw the Greater Werewolf art, this movie originally came to mind