Murders at Karlov Manor

Ill-Timed Explosion | Sorcery | | Draw two cards. Then you may discard two cards. When you do, Ill-Timed Explosion deals X damage to each creature, where X is the greatest mana value among cards discarded this way. | Aaron J. Riley

Kylox, Visionary Inventor | Legendary Creature | Viashino Artificer | Menace, ward {2}, haste Whenever Kylox, Visionary Inventor attacks, sacrifice any number of other creatures, then exile the top X cards of your library, where X is their total power. You may cast any number of instant and/or sorcery spells from among the exiled cards without paying their mana costs. | Lie Setiawan

Leyline of the Guildpact | Enchantment | | If Leyline of the Guildpact is in your opening hand, you may begin the game with it on the battlefield. Each nonland permanent you control is all colors. Lands you control are every basic land type in addition to their other types. | Daarken

Niv-Mizzet, Guildpact | Legendary Creature | Dragon Avatar | Flying, hexproof from multicolored Whenever Niv-Mizzet, Guildpact deals combat damage to a player, it deals X damage to any target, target player draws X cards, and you gain X life, where X is the number of different color pairs among permanents you control that are exactly two colors. | Chris Rallis

Thundering Falls | Land | Island Mountain | ({T}: Add {U} or {R}.) Thundering Falls enters the battlefield tapped. When Thundering Falls enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.) | Grady Frederick