Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Grave Sifter

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

Kindred Summons

Choose a creature type. Reveal cards from the top of your library until you reveal X creature cards of the chosen type, where X is the number of creatures you control of that type. Put those cards onto the battlefield, then shuffle the rest of the revealed cards into your library.

Steely Resolve

As Steely Resolve enters, choose a creature type.
Creatures of the chosen type have shroud. (They can't be the targets of spells or abilities.)

Crown of Vigor

Enchant creature
Enchanted creature gets +1/+1.
Sacrifice Crown of Vigor: Enchanted creature and other creatures that share a creature type with it get +1/+1 until end of turn.

Caller of the Hunt

As an additional cost to cast this spell, choose a creature type.
Caller of the Hunt's power and toughness are each equal to the number of creatures of the chosen type on the battlefield.

Alpha Status

Enchant creature
Enchanted creature gets +2/+2 for each other creature on the battlefield that shares a creature type with it.

Luminescent Rain

Choose a creature type. You gain 2 life for each permanent you control of that type.

Reins of the Vinesteed

Enchant creature
Enchanted creature gets +2/+2.
When enchanted creature dies, you may return Reins of the Vinesteed from your graveyard to the battlefield attached to a creature that shares a creature type with that creature.

Descendants' Path

At the beginning of your upkeep, reveal the top card of your library. If it's a creature card that shares a creature type with a creature you control, you may cast it without paying its mana cost. If you don't cast it, put it on the bottom of your library.

Elvish Soultiller

When Elvish Soultiller dies, choose a creature type. Shuffle all creature cards of that type from your graveyard into your library.

Tribal Forcemage

Morph {1}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Tribal Forcemage is turned face up, creatures of the creature type of your choice get +2/+2 and gain trample until end of turn.

For the Ancestors

Choose a creature type. Look at the top six cards of your library. You may reveal any number of cards of the chosen type from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.
Flashback {3}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Bloodline Shaman

{T}: Choose a creature type. Reveal the top card of your library. If that card is a creature card of the chosen type, put it into your hand. Otherwise, put it into your graveyard.