Loreseeker's Stone

{3}, {T}: Draw three cards. This ability costs {1} more to activate for each card in your hand.

Keleth, Sunmane Familiar

Whenever a commander you control attacks, put a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Krark, the Thumbless

Whenever you cast an instant or sorcery spell, flip a coin. If you lose the flip, return that spell to its owner's hand. If you win the flip, copy that spell, and you may choose new targets for the copy.
Partner (You can have two commanders if both have partner.)

Stonefury

Stonefury deals damage to target creature equal to the number of lands you control.

Prosperous Pirates

When Prosperous Pirates enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Pennon Blade

Equipped creature gets +1/+1 for each creature you control.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Strategic Planning

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Wild Celebrants

When Wild Celebrants enters, you may destroy target artifact.

Anointer of Valor

Flying
Whenever a creature attacks, you may pay {3}. When you do, put a +1/+1 counter on that creature.

Nadier's Nightblade

Whenever a token you control leaves the battlefield, each opponent loses 1 life and you gain 1 life.

Opal Palace

{T}: Add {C}.
{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

Undying Rage

Enchant creature
Enchanted creature gets +2/+2 and can't block.
When Undying Rage is put into a graveyard from the battlefield, return Undying Rage to its owner's hand.

Scrounging Bandar

Scrounging Bandar enters with two +1/+1 counters on it.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Scrounging Bandar onto another target creature.

Armory of Iroas

Whenever equipped creature attacks, put a +1/+1 counter on it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Sanitarium Skeleton

{2}{B}: Return Sanitarium Skeleton from your graveyard to your hand.

Pirate's Cutlass

When this Equipment enters, attach it to target Pirate you control.
Equipped creature gets +2/+1.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)