Forgotten Ancient

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

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Hidden Guerrillas

When an opponent casts an artifact spell, if Hidden Guerrillas is an enchantment, Hidden Guerrillas becomes a 5/3 Soldier creature with trample.

Naturalize

Land Grant

If you have no land cards in hand, you may reveal your hand rather than pay this spell's mana cost.
Search your library for a Forest card, reveal that card, put it into your hand, then shuffle.

Sungrass Egg

{2}, {T}, Sacrifice Sungrass Egg: Add {G}{W}. Draw a card.

Shadowblood Egg

{2}, {T}, Sacrifice Shadowblood Egg: Add {B}{R}. Draw a card.

Darkwater Egg

{2}, {T}, Sacrifice Darkwater Egg: Add {U}{B}. Draw a card.

Mossfire Egg

{2}, {T}, Sacrifice Mossfire Egg: Add {R}{G}. Draw a card.

Compost

Whenever a black card is put into an opponent's graveyard from anywhere, you may draw a card.

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)

Skycloud Egg

{2}, {T}, Sacrifice Skycloud Egg: Add {W}{U}. Draw a card.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Chromatic Sphere

{1}, {T}, Sacrifice Chromatic Sphere: Add one mana of any color. Draw a card.

Eladamri's Vineyard

At the beginning of each player's first main phase, that player adds {G}{G}.

Deranged Hermit

Echo {3}{G}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Deranged Hermit enters, create four 1/1 green Squirrel creature tokens.
Squirrel creatures get +1/+1.

Nantuko Shrine

Whenever a player casts a spell, that player creates X 1/1 green Squirrel creature tokens, where X is the number of cards in all graveyards with the same name as that spell.