Counterbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sanctum Weaver

{T}: Add X mana of any one color, where X is the number of enchantments you control.

Kynaios and Tiro of Meletis

At the beginning of your end step, draw a card. Each player may put a land card from their hand onto the battlefield, then each opponent who didn't draws a card.

Seal of Primordium

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

Exploration

You may play an additional land on each of your turns.

Kenrith's Transformation

Enchant creature
When Kenrith's Transformation enters, draw a card.
Enchanted creature loses all abilities and is a green Elk creature with base power and toughness 3/3. (It loses all other card types and creature types.)

Sythis, Harvest's Hand

Whenever you cast an enchantment spell, you gain 1 life and draw a card.

Psychic Surgery

Whenever an opponent shuffles their library, you may look at the top two cards of that library. You may exile one of those cards. Then put the rest on top of that library in any order.

Serra's Sanctum

{T}: Add {W} for each enchantment you control.

Seal of Cleansing

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.