Flash
Flying
Dreamcaller Siren can block only creatures with flying.
When Dreamcaller Siren enters the battlefield, if you control another Pirate, tap up to two target nonland permanents.

: Add .
, , Sacrifice Dreamstone Hedron: Draw three cards.

Flying
Whenever a Dragon you control attacks, bolster 2. (Choose a creature with the least toughness among creatures you control and put two +1/+1 counters on it.)

Drover of the Mighty gets +2/+2 as long as you control a Dinosaur.
: Add one mana of any color.

Equipped creature gets +1/+0.
When equipped creature deals combat damage to a player, unattach Elbrus, the Binding Blade, then transform it.
Equip

[+1]: Create three 1/1 white Soldier creature tokens.
[−3]: Destroy all creatures with power 4 or greater.
[−7]: You get an emblem with "Creatures you control get +2/+2 and have flying."

Whenever you cast an artifact spell, you may pay . If you do, Embersmith deals 1 damage to any target.

Indestructible
As long as your devotion to white and blue is less than seven, Ephara isn't a creature.
At the beginning of each upkeep, if you had another creature enter the battlefield under your control last turn, draw a card.

Exile target creature with converted mana cost 3 or greater.

Creatures you control get +1/+1.
Creatures your opponents control get -1/-1.
: Exile target card from an opponent's graveyard. If it was a creature card, you create a 1/1 white and black Spirit creature token with flying.

Destroy target creature if it has converted mana cost 2 or less.
Revolt — Destroy that creature if it has converted mana cost 4 or less instead if a permanent you controlled left the battlefield this turn.

Create two 3/3 green Centaur enchantment creature tokens. If it's your turn, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

When Festering Newt dies, target creature an opponent controls gets -1/-1 until end of turn. That creature gets -4/-4 instead if you control a creature named Bogbrew Witch.

Fiery Temper deals 3 damage to any target.
Madness (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Search your library for two cards. Put one into your hand and the other into your graveyard. Then shuffle your library.

When Garruk Relentless has two or fewer loyalty counters on him, transform him.
[0]: Garruk Relentless deals 3 damage to target creature. That creature deals damage equal to its power to him.
[0]: Create a 2/2 green Wolf creature token.

[0]: Create two 2/2 black and green Wolf creature tokens with "When this creature dies, put a loyalty counter on each Garruk you control."
[−3]: Destroy target creature. Draw a card.
[−6]: You get an emblem with "Creatures you control get +3/+3 and have trample."

[+1]: Reveal the top card of your library. If it's a creature card, put it into your hand. Otherwise, put it on the bottom of your library.
[−2]: Target creature you control deals damage equal to its power to another target creature.
[−7]: Until end of turn, creatures you control gain "You may have this creature assign its combat damage as though it weren't blocked."

[+1]: Create a 1/1 black Wolf creature token with deathtouch.
[−1]: Sacrifice a creature. If you do, search your library for a creature card, reveal it, put it into your hand, then shuffle your library.
[−3]: Creatures you control gain trample and get +X/+X until end of turn, where X is the number of creature cards in your graveyard.

[+1]: Until end of turn, Gideon, Ally of Zendikar becomes a 5/5 Human Soldier Ally creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
[0]: Create a 2/2 white Knight Ally creature token.
[−4]: You get an emblem with "Creatures you control get +1/+1."