Gravity Well

Whenever a creature with flying attacks, it loses flying until end of turn.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Selesnya Guildgate

Selesnya Guildgate enters tapped.
{T}: Add {G} or {W}.

Terra Eternal

Light of Day

Harmonious Archon

Flying
Non-Archon creatures have base power and toughness 3/3.
When Harmonious Archon enters, create two 1/1 white Human creature tokens.

Plains

Leafkin Druid

{T}: Add {G}. If you control four or more creatures, add {G}{G} instead.

Tendershoot Dryad

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
At the beginning of each upkeep, create a 1/1 green Saproling creature token.
Saprolings you control get +2/+2 as long as you have the city's blessing.

Tomik, Distinguished Advokist

Flying
Lands on the battlefield and land cards in graveyards can't be the targets of spells or abilities your opponents control.
Your opponents can't play land cards from graveyards.

Forest

Sporecrown Thallid

Each other creature you control that's a Fungus or Saproling gets +1/+1.

Shifting Sky

As Shifting Sky enters, choose a color.
All nonland permanents are the chosen color.

Arcane Adaptation

As Arcane Adaptation enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Simic Guildgate

Simic Guildgate enters tapped.
{T}: Add {G} or {U}.

Absolute Grace

All creatures have protection from black.

Life and Limb

All Forests and all Saprolings are 1/1 green Saproling creatures and Forest lands in addition to their other types. (They're affected by summoning sickness.)

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Night Soil

{1}, Exile two creature cards from a single graveyard: Create a 1/1 green Saproling creature token.

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Leyline of Abundance

If Leyline of Abundance is in your opening hand, you may begin the game with it on the battlefield.
Whenever you tap a creature for mana, add an additional {G}.
{6}{G}{G}: Put a +1/+1 counter on each creature you control.

Nissa, Who Shakes the World

Whenever you tap a Forest for mana, add an additional {G}.
+1: Put three +1/+1 counters on up to one target noncreature land you control. Untap it. It becomes a 0/0 Elemental creature with vigilance and haste that's still a land.
−8: You get an emblem with "Lands you control have indestructible." Search your library for any number of Forest cards, put them onto the battlefield tapped, then shuffle.