Keyword: Partner

As an additional cost to cast this spell, you may sacrifice any number of artifacts and/or creatures. This spell costs less to cast for each permanent sacrificed this way and less to cast for each other artifact or creature you’ve sacrificed this turn.
Trample
Partner (You can have two commanders if both have partner.)

Flying
Spells your opponents cast that target one or more commanders you control cost more to cast.
Partner (You can have two commanders if both have partner.)

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

At the beginning of combat on your turn, you may pay . When you do, distribute X +1/+1 counters among any number of target Elves.
Partner (You can have two commanders if both have partner.)

Flying
Spells your opponents cast that target one or more commanders you control cost more to cast.
Partner (You can have two commanders if both have partner.)

Deathtouch
Whenever Silas Renn, Seeker Adept deals combat damage to a player, choose target artifact card in your graveyard. You may cast that card this turn.
Partner (You can have two commanders if both have partner.)

: Add for each card you’ve drawn this turn.
Partner (You can have two commanders if both have partner.)

As long as it’s your turn, creature tokens you control get +1/+4.
: Create a 1/1 white Soldier creature token.
Partner (You can have two commanders if both have partner.)

+2: Create two 0/1 black Thrull creature tokens.
+1: You may sacrifice another creature or planeswalker. If you do, draw two cards, then draw another card if the sacrificed permanent was a commander.
−10: Gain control of all commanders. Put all commanders from the command zone onto the battlefield under your control.
Tevesh Szat, Doom of Fools can be your commander.
Partner

At the beginning of combat on your turn, creatures you control get +3/+3 and gain trample until end of turn.
: Until end of turn, target land you control becomes a 1/1 Elemental creature with vigilance, indestructible, and haste. It’s still a land.
Partner (You can have two commanders if both have partner.)

Reach
Whenever another permanent enters the battlefield under your control, if it wasn’t put onto the battlefield with this ability, you may put a permanent card with equal or lesser converted mana cost from your hand onto the battlefield.
Partner (You can have two commanders if both have partner.)

Flying
Tap another untapped creature you control with flying: Radiant, Serra Archangel gains protection from the color of your choice until end of turn.
Partner (You can have two commanders if both have partner.)

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.)

Flying
If you would scry a number of cards, draw that many cards instead.
Partner (You can have two commanders if both have partner.)

At the beginning of combat on your turn, you may attach any number of Auras and Equipment you control to target permanent or player.
Partner (You can have two commanders if both have partner.)

Ghost of Ramirez DePietro can’t be blocked by creatures with toughness 3 or greater.
Whenever Ghost of Ramirez DePietro deals combat damage to a player, choose up to one target card in a graveyard that was discarded or put there from a library this turn. Put that card into its owner’s hand.
Partner (You can have two commanders if both have partner.)

Menace
Whenever one or more Pirates you control deal damage to your opponents, exile the top card of each of those opponents’ libraries. You may play those cards this turn, and you may spend mana as though it were mana of any color to cast those spells.
Partner (You can have two commanders if both have partner.)

When Ich-Tekik, Salvage Splicer enters the battlefield, create a 3/3 colorless Golem artifact creature token.
Whenever an artifact is put into a graveyard from the battlefield, put a +1/+1 counter on Ich-Tekik and a +1/+1 counter on each Golem you control.
Partner (You can have two commanders if both have partner.)

Artifacts you control have protection from each converted mana cost among artifacts you control.
Partner (You can have two commanders if both have partner.)

Flying
Whenever one or more Pirates you control deal damage to your opponents, you create a Treasure token for each opponent dealt damage. (It’s an artifact with “, Sacrifice this artifact: Add one mana of any color.”)
Partner (You can have two commanders if both have partner.)

Flying
Whenever another creature dies, put two +1/+1 counters on Sengir, the Dark Baron.
Whenever another player loses the game, you gain life equal to that player’s life total as the turn began.
Partner (You can have two commanders if both have partner.)

At the beginning of each player’s end step, that player may draw a card if a player other than you lost life this turn.
Partner (You can have two commanders if both have partner.)

Whenever a token you control leaves the battlefield, put a +1/+1 counter on Nadier, Agent of the Duskenel.
When Nadier leaves the battlefield, create a number of 1/1 green Elf Warrior creature tokens equal to its power.
Partner (You can have two commanders if both have partner.)

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
Creatures your opponents control without flying or reach can’t block creatures with power 2 or less.
Partner (You can have two commanders if both have partner.)

Whenever Armix, Filigree Thrasher attacks, you may discard a card. When you do, target creature defending player controls gets -X/-X until end of turn, where X is the number of artifacts you control plus the number of artifact cards in your graveyard.
Partner (You can have two commanders if both have partner.)