Flying
When Aven Eternal enters the battlefield, amass 1. (Put a +1/+1 counter on an Army you control. If you don't control one, create a 0/0 black Zombie Army creature token first.)

: Add . Spend this mana only to cast an Elemental spell or a Chandra planeswalker spell.

Enchant creature
When Colossification enters the battlefield, tap enchanted creature.
Enchanted creature gets +20/+20.

Other Elementals you control get +1/+0.
: Creeping Trailblazer gets +1/+1 until end of turn for each Elemental you control.

Flying

Put target creature with power 4 or greater on the bottom of its owner's library.

When Eternal Skylord enters the battlefield, amass 2. (Put two +1/+1 counters on an Army you control. If you don't control one, create a 0/0 black Zombie Army creature token first.)
Zombie tokens you control have flying.

Commander spells you cast have cascade. (Whenever you cast a commander, exile cards from the top of your library until you exile a nonland card with lesser converted mana cost. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.
Cycling (, Discard this card: Draw a card.)

You may have Glasspool Mimic enter the battlefield as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.

Glasspool Shore enters the battlefield tapped.
: Add .

Sliver creatures you control have ", Discard a card: Draw a card."

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

: Add .

Target player returns each commander they control from the battlefield to the command zone.
Draw a card.

Flying
When Rapacious Dragon enters the battlefield, create two Treasure tokens. (They're artifacts with ", Sacrifice this artifact: Add one mana of any color.")

Whenever Risen Reef or another Elemental enters the battlefield under your control, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

: Add .

Whenever Scorch Spitter attacks, it deals 1 damage to the player or planeswalker it's attacking.

Flying
When Sphinx of Enlightenment enters the battlefield, target opponent draws a card and you draw three cards.