Sliver Legion

All Sliver creatures get +1/+1 for each other Sliver on the battlefield.

Forest

Kavu Primarch

Kicker {4} (You may pay an additional {4} as you cast this spell.)
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.)
If Kavu Primarch was kicked, it enters with four +1/+1 counters on it.

Plains

Mountain

Metallic Sliver

Llanowar Augur

Sacrifice Llanowar Augur: Target creature gets +3/+3 and gains trample until end of turn. Activate only during your upkeep.

Mesmeric Sliver

All Slivers have "When this permanent enters, you may fateseal 1." (To fateseal 1, its controller looks at the top card of an opponent's library, then they may put that card on the bottom of that library.)

Venser's Diffusion

Return target nonland permanent or suspended card to its owner's hand.

Island

Tolaria West

Tolaria West enters tapped.
{T}: Add {U}.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with mana value 0, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Centaur Omenreader

As long as Centaur Omenreader is tapped, creature spells you cast cost {2} less to cast.

Saproling

Petrified Plating

Enchant creature
Enchanted creature gets +2/+2.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Lymph Sliver

All Sliver creatures have absorb 1. (If a source would deal damage to a Sliver, prevent 1 of that damage.)

Frenzy Sliver

All Sliver creatures have frenzy 1. (Whenever a Sliver attacks and isn't blocked, it gets +1/+0 until end of turn.)

Swamp

Rites of Flourishing

At the beginning of each player's draw step, that player draws an additional card.
Each player may play an additional land on each of their turns.

Ghostfire

Ghostfire is colorless.
Ghostfire deals 3 damage to any target.

Skizzik Surger

Haste
Echo—Sacrifice two lands. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Imperiosaur

Spend only mana produced by basic lands to cast this spell.

Spark Elemental

Trample, haste
At the beginning of the end step, sacrifice Spark Elemental.

Emblem of the Warmind

Enchant creature you control
Creatures you control have haste.

Sliversmith

{1}, {T}, Discard a card: Create a 1/1 colorless Sliver artifact creature token named Metallic Sliver.

Virulent Sliver

All Sliver creatures have poisonous 1. (Whenever a Sliver deals combat damage to a player, that player gets a poison counter. A player with ten or more poison counters loses the game.)