Combo

Soul of the Harvest

Trample
Whenever another nontoken creature you control enters, you may draw a card.

Barrage of Expendables

{R}, Sacrifice a creature: This enchantment deals 1 damage to any target.

Ramp

Elvish Mystic

Grumgully, the Generous

Each other non-Human creature you control enters with an additional +1/+1 counter on it.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Removal 

Song of the Dryads

Enchant permanent
Enchanted permanent is a colorless Forest land.

Persist

Thunderblust

Haste
This creature has trample as long as it has a -1/-1 counter on it.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Tutor

Signal the Clans

Search your library for three creature cards and reveal them. If you reveal three cards with different names, choose one of them at random and put that card into your hand. Shuffle the rest into your library.

Sacrifice 

Goblin Chirurgeon

Sacrifice a Goblin: Regenerate target creature.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Elvish Pioneer

When this creature enters, you may put a basic land card from your hand onto the battlefield tapped.

Fyndhorn Elves

Lesser Masticore

As an additional cost to cast this spell, discard a card.
{4}: This creature deals 1 damage to target creature.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Fecundity

Whenever a creature dies, that creature's controller may draw a card.

Quirion Elves

As this creature enters, choose a color.
{T}: Add {G}.
{T}: Add one mana of the chosen color.

Gruul Signet

Payoff 

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Aerie Ouphes

Sacrifice this creature: It deals damage equal to its power to target creature with flying.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Furystoke Giant

When this creature enters, other creatures you control gain "{T}: This creature deals 2 damage to any target" until end of turn.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Counters

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Path of Discovery

Whenever a creature you control enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)

Goblin Bombardment

Sacrifice a creature: This enchantment deals 1 damage to any target.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Fertilid

This creature enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from this creature: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. This artifact deals 1 damage to you.

Sol Ring

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Thermopod

{S}: This creature gains haste until end of turn. ({S} can be paid with one mana from a snow source.)
Sacrifice a creature: Add {R}.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Kessig Wolf Run

{T}: Add {C}.
{X}{R}{G}, {T}: Target creature gets +X/+0 and gains trample until end of turn.

Gate to the Afterlife

Whenever a nontoken creature you control dies, you gain 1 life. Then you may draw a card. If you do, discard a card.
{2}, {T}, Sacrifice this artifact: Search your graveyard, hand, and/or library for a card named God-Pharaoh's Gift and put it onto the battlefield. If you search your library this way, shuffle. Activate only if there are six or more creature cards in your graveyard.

Birthing Pod

({G/P} can be paid with either {G} or 2 life.)
{1}{G/P}, {T}, Sacrifice a creature: Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on this creature.
At the beginning of your upkeep, you may move any number of +1/+1 counters from this creature onto other creatures.

Devoted Druid

{T}: Add {G}.
Put a -1/-1 counter on this creature: Untap this creature.

Scuzzback Marauders

Trample
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Ashnod's Altar

Shared Summons

Search your library for up to two creature cards with different names, reveal them, put them into your hand, then shuffle.

Elemental Bond

Whenever a creature you control with power 3 or greater enters, draw a card.

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Evolutionary Leap

{G}, Sacrifice a creature: Reveal cards from the top of your library until you reveal a creature card. Put that card into your hand and the rest on the bottom of your library in a random order.

Blasting Station

{T}, Sacrifice a creature: This artifact deals 1 damage to any target.
Whenever a creature enters, you may untap this artifact.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Woodfall Primus

Trample
When this creature enters, destroy target noncreature permanent.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Outpost Siege

As this enchantment enters, choose Khans or Dragons.
• Khans — At the beginning of your upkeep, exile the top card of your library. Until end of turn, you may play that card.
• Dragons — Whenever a creature you control leaves the battlefield, this enchantment deals 1 damage to any target.

Lignify

Enchant creature
Enchanted creature is a Treefolk with base power and toughness 0/4 and loses all abilities.

Decimate

Destroy target artifact, target creature, target enchantment, and target land. (You can't cast this spell unless you have legal choices for all its targets.)

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Gruul Turf

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Draw

Harmonize

Garruk's Packleader

Whenever another creature you control with power 3 or greater enters, you may draw a card.

Llanowar Elves

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.

Finale of Devastation

Search your library and/or graveyard for a creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle. If X is 10 or more, creatures you control get +X/+X and gain haste until end of turn.

Animation Module

Whenever one or more +1/+1 counters are put on a permanent you control, you may pay {1}. If you do, create a 1/1 colorless Servo artifact creature token.
{3}, {T}: Choose a counter on target permanent or player. Give that permanent or player another counter of that kind.

Pir, Imaginative Rascal

Partner with Toothy, Imaginary Friend (When this creature enters, target player may put Toothy into their hand from their library, then shuffle.)
If one or more counters would be put on a permanent your team controls, that many plus one of each of those kinds of counters are put on that permanent instead.

Hull Breach

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Destroy target artifact and target enchantment.

Demonmail Hauberk

Equipped creature gets +4/+2.
Equip—Sacrifice a creature.

Boreal Druid

Cauldron of Souls

{T}: Choose any number of target creatures. Each of those creatures gains persist until end of turn. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Hissing Iguanar

Whenever another creature dies, you may have this creature deal 1 damage to target player or planeswalker.

Spawning Pit

Sacrifice a creature: Put a charge counter on this artifact.
{1}, Remove two charge counters from this artifact: Create a 2/2 colorless Spawn artifact creature token.