Thran Quarry

At the beginning of the end step, if you control no creatures, sacrifice Thran Quarry.
: Add one mana of any color.

Oath of Scholars

At the beginning of each player’s upkeep, that player chooses target player who has more cards in hand than they do and is their opponent. The first player may discard their hand and draw three cards.

Shifting Wall

Defender (This creature can’t attack.)
Shifting Wall enters the battlefield with X +1/+1 counters on it.

Wall of Razors

Defender (This creature can’t attack.)
First strike