Obelisk of Urd

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +2/+2.

Thunderfoot Baloth

Trample
Lieutenant — As long as you control your commander, this creature gets +2/+2 and other creatures you control get +2/+2 and have trample.

Baru, Wurmspeaker

Wurms you control get +2/+2 and have trample.
{7}{G}, {T}: Create a 4/4 green Wurm creature token. This ability costs {X} less to activate, where X is the greatest power among Wurms you control.

Fyndhorn Brownie

Seeker of Skybreak

Spidery Grasp

Untap target creature. It gets +2/+4 and gains reach until end of turn. (It can block creatures with flying.)

Puppet Strings

{2}, {T}: You may tap or untap target creature.

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.

Nature's Cloak

Green creatures you control gain forestwalk until end of turn. (They can't be blocked as long as defending player controls a Forest.)

Gaea's Anthem

Guardian Augmenter

Flash
Commander creatures you control get +2/+2.
Commanders you control have hexproof.

Ornamental Courage

Untap target creature. It gets +1/+3 until end of turn.

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Staff of Domination

{1}: Untap this artifact.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Scryb Ranger

Flash
Flying, protection from blue
Return a Forest you control to its owner's hand: Untap target creature. Activate only once each turn.

Provoke

Untap target creature you don't control. That creature blocks this turn if able.
Draw a card.

Steady Aim

Untap target creature. It gets +1/+4 and gains reach until end of turn.

End-Raze Forerunners

Vigilance, trample, haste
When this creature enters, other creatures you control get +2/+2 and gain vigilance and trample until end of turn.

Wirewood Symbiote

Return an Elf you control to its owner's hand: Untap target creature. Activate only once each turn.

Gift of Growth

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Untap target creature. It gets +2/+2 until end of turn. If this spell was kicked, that creature gets +4/+4 until end of turn instead.

Jandor's Saddlebags

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Aim High

Untap target creature. It gets +2/+2 and gains reach until end of turn.

Quirion Ranger

Return a Forest you control to its owner's hand: Untap target creature. Activate only once each turn.