Twinflame Travelers

Flying
If a triggered ability of another Elemental you control triggers, it triggers an additional time.

Brighthearth Banneret

Elemental spells and Warrior spells you cast cost {1} less to cast.
Reinforce 1—{1}{R} ({1}{R}, Discard this card: Put a +1/+1 counter on target creature.)

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Eclipsed Realms

As this land enters, choose Elemental, Elf, Faerie, Giant, Goblin, Kithkin, Merfolk, or Treefolk.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a spell of the chosen type or activate an ability of a source of the chosen type.

Animar, Soul of Elements

Protection from white and from black
Whenever you cast a creature spell, put a +1/+1 counter on Animar.
Creature spells you cast cost {1} less to cast for each +1/+1 counter on Animar.

Muster the Departed

When this enchantment enters, create a 1/1 white Spirit creature token with flying.
Morbid — At the beginning of your end step, if a creature died this turn, populate. (Create a token that's a copy of a creature token you control.)

Mystic Reflection

Choose target nonlegendary creature. The next time one or more creatures or planeswalkers enter this turn, they enter as copies of the chosen creature.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Ashling, the Limitless

Elemental permanent spells you cast from your hand gain evoke {4} as you cast them. (If you cast a spell for its evoke cost, it's sacrificed when it enters.)
Whenever you sacrifice a nontoken Elemental, create a token that's a copy of it. The token gains haste until end of turn. At the beginning of your next end step, sacrifice it unless you pay {W}{U}{B}{R}{G}.

Flamekin Harbinger

When this creature enters, you may search your library for an Elemental card, reveal it, then shuffle and put that card on top.

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

Grave Sifter

When this creature enters, each player chooses a creature type and returns any number of cards of that type from their graveyard to their hand.