Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Sylvan Caryatid

Defender, hexproof
{T}: Add one mana of any color.

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Ashiok, Nightmare Weaver

+2: Exile the top three cards of target opponent's library.
−X: Put a creature card with mana value X exiled with Ashiok, Nightmare Weaver onto the battlefield under your control. That creature is a Nightmare in addition to its other types.
−10: Exile all cards from all opponents' hands and graveyards.

Nimbus Naiad

Bestow {4}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
Enchanted creature gets +2/+2 and has flying.

Karametra's Acolyte

{T}: Add an amount of {G} equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)