Cavalier of Flame

{1}{R}: Creatures you control get +1/+0 and gain haste until end of turn.
When Cavalier of Flame enters the battlefield, discard any number of cards, then draw that many cards.
When Cavalier of Flame dies, it deals X damage to each opponent and each planeswalker they control, where X is the number of land cards in your graveyard.

Cloud Manta

Riftwing Cloudskate

Flying
When Riftwing Cloudskate enters the battlefield, return target permanent to its owner's hand.
Suspend 3—{1}{U} (Rather than cast this card from your hand, you may pay {1}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Terravore

Trample
Terravore's power and toughness are each equal to the number of land cards in all graveyards.

Skyreach Manta

Sunburst (This enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it.)
Flying

Riptide Biologist

Protection from Beasts
Morph {2}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Plaxmanta

Flash
When Plaxmanta enters the battlefield, creatures you control gain shroud until end of turn. (They can't be the targets of spells or abilities.)
When Plaxmanta enters the battlefield, sacrifice it unless {G} was spent to cast it.

Cloudskate

Flying
Fading 3 (This creature enters the battlefield with three fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)

Deepglow Skate

When Deepglow Skate enters the battlefield, double the number of each kind of counter on any number of target permanents.