Overabundance

Whenever a player taps a land for mana, that player adds one mana of any type that land produced, and this enchantment deals 1 damage to the player.

Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

True Conviction

Creatures you control have double strike and lifelink.

Kalonian Hydra

Trample
This creature enters with four +1/+1 counters on it.
Whenever this creature attacks, double the number of +1/+1 counters on each creature you control.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on this creature.

Mirari's Wake

Creatures you control get +1/+1.
Whenever you tap a land for mana, add one mana of any type that land produced.

Johan

At the beginning of combat on your turn, you may have Johan gain "Johan can't attack" until end of combat. If you do, attacking doesn't cause creatures you control to tap this combat if Johan is untapped.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Heartbeat of Spring

Zhur-Taa Ancient

Gisela, Blade of Goldnight

Flying, first strike
If a source would deal damage to an opponent or a permanent an opponent controls, that source deals double that damage to that player or permanent instead.
If a source would deal damage to you or a permanent you control, prevent half that damage, rounded up.

Zopandrel, Hunger Dominus

Reach
At the beginning of each combat, double the power and toughness of each creature you control until end of turn.
{G/P}{G/P}, Sacrifice two other creatures: Put an indestructible counter on Zopandrel. ({G/P} can be paid with either {G} or 2 life.)

Pathbreaker Ibex

Whenever this creature attacks, creatures you control gain trample and get +X/+X until end of turn, where X is the greatest power among creatures you control.