Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

Price of Progress

Price of Progress deals damage to each player equal to twice the number of nonbasic lands that player controls.

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Reckless Fireweaver

Whenever an artifact you control enters, this creature deals 1 damage to each opponent.

Akroma's Memorial

Creatures you control have flying, first strike, vigilance, trample, haste, and protection from black and from red.

Kokusho, the Evening Star

Flying
When Kokusho dies, each opponent loses 5 life. You gain life equal to the life lost this way.

Dragon

The Monarch

Skyline Despot

Flying
When this creature enters, you become the monarch.
At the beginning of your upkeep, if you're the monarch, create a 5/5 red Dragon creature token with flying.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Secret Lair Drop