Through the Breach is the closest you can get to sneaking a giant monster from your hand into play. Luckily, it’s a pretty solid one and can even be cast at instant speed. If you’re going to put something big into play, let’s make it the biggest possible and just get Emrakul, the Aeons Torn into play with haste.
From there, you need to actually set up your big combination. Serum Visions and Sleight of Hand are the best card selection options you have on the cheap in Modern, thanks to the banning of Preordain and Ponder.
Remand and Izzet Charm pull double-duty as interaction and potential card draw. When your goal is to both find a 2-card combo and protect it (as well as the lands to actually cast them), these are some excellent inclusions. Cryptic Command and Repeal continue the tradition of both impacting the board and drawing cards.
This deck does a lot to cycle through cards and can make excellent use of arguably the best card in Modern (Snapcaster Mage) and the best removal spell (Lightning Bolt). Combine that with the most powerful creature in all of Magic, and we have the makings of a pretty sweet and solid deck!