Hagra Diabolist

Whenever Hagra Diabolist or another Ally you control enters, you may have target player lose life equal to the number of Allies you control.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sea Gate Loremaster

{T}: Draw a card for each Ally you control.

Neurok Stealthsuit

Equipped creature has shroud. (It can't be the target of spells or abilities.)
{U}{U}: Attach Neurok Stealthsuit to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Necrotic Sliver

All Slivers have "{3}, Sacrifice this permanent: Destroy target permanent."

Kazuul Warlord

Whenever Kazuul Warlord or another Ally you control enters, you may put a +1/+1 counter on each Ally creature you control.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Gemhide Sliver

All Slivers have "{T}: Add one mana of any color."

Kabira Evangel

Whenever Kabira Evangel or another Ally you control enters, you may choose a color. If you do, Allies you control gain protection from the chosen color until end of turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Ondu Cleric

Whenever Ondu Cleric or another Ally you control enters, you may gain life equal to the number of Allies you control.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Rukarumel, Biologist

As Rukarumel, Biologist enters, choose a creature type.
Slivers you control and nontoken creatures you control are the chosen type in addition to their other creature types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 1/1 colorless Sliver creature token.

Lantern Scout

Rally — Whenever Lantern Scout or another Ally you control enters, creatures you control gain lifelink until end of turn.

Harabaz Druid

{T}: Add X mana of any one color, where X is the number of Allies you control.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Hero of Goma Fada

Rally — Whenever Hero of Goma Fada or another Ally you control enters, creatures you control gain indestructible until end of turn.

Cultivate

Kalastria Healer

Rally — Whenever Kalastria Healer or another Ally you control enters, each opponent loses 1 life and you gain 1 life.

Harmonic Sliver

All Slivers have "When this permanent enters, destroy target artifact or enchantment."

Manaweft Sliver

Sliver creatures you control have "{T}: Add one mana of any color."

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.