Ruby Medallion

Red spells you cast cost {1} less to cast.

Laelia, the Blade Reforged

Haste
Whenever Laelia attacks, exile the top card of your library. You may play that card this turn.
Whenever one or more cards are put into exile from your library and/or your graveyard, put a +1/+1 counter on Laelia.

Ilharg, the Raze-Boar

Trample
Whenever Ilharg attacks, you may put a creature card from your hand onto the battlefield tapped and attacking. Return that creature to your hand at the beginning of the next end step.
When Ilharg dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Inti, Seneschal of the Sun

Whenever you attack, you may discard a card. When you do, put a +1/+1 counter on target attacking creature. It gains trample until end of turn.
Whenever you discard one or more cards, exile the top card of your library. You may play that card until your next end step.

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Gimli of the Glittering Caves

Double strike
Whenever another legendary creature you control enters, put a +1/+1 counter on Gimli.
Whenever Gimli deals combat damage to a player, create a Treasure token.

Elturel Survivors

Trample, myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
As long as this creature is attacking, it gets +X/+0, where X is the number of lands defending player controls.

Vincent, Vengeful Atoner

Menace
Whenever one or more creatures you control deal combat damage to a player, put a +1/+1 counter on Vincent.
Chaos — Whenever Vincent deals combat damage to an opponent, it deals that much damage to each other opponent if Vincent's power is 7 or greater.

Balor

Flying
Whenever this creature attacks or dies, choose one or more. Each mode must target a different player.
• Target opponent draws three cards, then discards three cards at random.
• Target opponent sacrifices a nontoken artifact of their choice.
• This creature deals damage to target opponent equal to the number of cards in their hand.

Arcane Signet

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

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Dragonhawk, Fate's Tempest

Flying
Whenever Dragonhawk enters or attacks, exile the top X cards of your library, where X is the number of creatures you control with power 4 or greater. You may play those cards until your next end step. At the beginning of your next end step, Dragonhawk deals 2 damage to each opponent for each of those cards that are still exiled.

Breeches, Eager Pillager

First strike
Whenever a Pirate you control attacks, choose one that hasn't been chosen this turn —
• Create a Treasure token.
• Target creature can't block this turn.
• Exile the top card of your library. You may play it this turn.

Krenko, Tin Street Kingpin

Whenever Krenko attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power.

Star Athlete

Menace
Whenever this creature attacks, choose up to one target nonland permanent. Its controller may sacrifice it. If they don't, this creature deals 5 damage to that player.
Blitz {3}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Professional Face-Breaker

Menace
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token.
Sacrifice a Treasure: Exile the top card of your library. You may play that card this turn.

Crimson Caravaneer

Double strike, trample
Whenever this creature deals combat damage to a player, create a Junk token. (It's an artifact with "{T}, Sacrifice this token: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")

Rose, Cutthroat Raider

First strike
Raid — At end of combat on your turn, if you attacked this turn, create a Junk token for each opponent you attacked. (It's an artifact with "{T}, Sacrifice this token: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
Whenever you sacrifice a Junk, add {R}.

Gogo, Mysterious Mime

At the beginning of combat on your turn, you may have Gogo become a copy of another target creature you control until end of turn, except its name is Gogo, Mysterious Mime. If you do, Gogo and that creature each get +2/+0 and gain haste until end of turn and attack this turn if able.

Captain Lannery Storm

Haste
Whenever Captain Lannery Storm attacks, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Whenever you sacrifice a Treasure, Captain Lannery Storm gets +1/+0 until end of turn.

Sol Ring

Bladegriff Prototype

Flying
Whenever this creature deals combat damage to a player, destroy target nonland permanent of that player's choice that one of your opponents controls.