7 Varragoth, Bloodsky Sire Tutoring is one of the most powerful abilities in Magic: The Gathering, allowing you to search your library for a specific card you want
The amount of mana it generates, combined with being a win condition on its own, is just massive for a Modern card
Use commons and uncommons to improve your pre-cons and get deck building experience : The common and uncommon wildcards are the most abundant and the easiest to get, so try to tinker around with those to get some experience in deck building and crafting cards
If you could get your hands on just one of them, which one would it be
Closing out September with a bang, MagicCon: Atlanta delivered the motherload of all announcements
Most opponents are not gonna risk that kind of blowout a second time, so you end up getting a huge unblockable threat for just one green mana