Mountain

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Noise Marine

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Sonic Blaster — When this creature enters, it deals damage equal to the number of spells you've cast this turn to any target.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Spider-Gwen, Free Spirit

Reach
Whenever Spider-Gwen becomes tapped, you may discard a card. If you do, draw a card.

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.)

Canoptek Spyder

Flying
Fabricator Claw Array — Whenever another nontoken artifact creature or Vehicle you control enters, draw a card.

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Pumpkin Bombs

{T}, Discard two cards: Draw three cards, then put a fuse counter on this artifact. It deals damage equal to the number of fuse counters on it to target opponent. They gain control of this artifact.

Bedlam

City on Fire

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 a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Disrupt Decorum

Goad all creatures you don't control. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Ruby Medallion

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

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.

The Fire Crystal

Red spells you cast cost {1} less to cast.
Creatures you control have haste.
{4}{R}{R}, {T}: Create a token that's a copy of target creature you control. Sacrifice it at the beginning of the next end step.

Spider-Punk

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Other Spiders you control have riot.
Spells and abilities can't be countered.
Damage can't be prevented.

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Masked Meower

Haste
Discard a card, Sacrifice this creature: Draw a card.

The Mary Janes

This spell costs {1} less to cast for each creature that attacked this turn.
Menace (This creature can't be blocked except by two or more creatures.)

Chainsaw

When this Equipment enters, it deals 3 damage to up to one target creature.
Whenever one or more creatures die, put a rev counter on this Equipment.
Equipped creature gets +X/+0, where X is the number of rev counters on this Equipment.
Equip {3}

Ghost-Spider, Gwen Stacy

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Ghost-Spider attacks, she deals X damage to defending player, where X is the number of attacking creatures.

Rock Star

Reach
When this creature enters, you may discard a card. If you do, reveal the top five cards of your library. Ask a person outside the game to choose which of them is most like a rock band. Put that card into your hand and the rest on the bottom of your library in a random order.

Devastating Onslaught

Create X tokens that are copies of target artifact or creature you control. Those tokens gain haste until end of turn. Sacrifice them at the beginning of the next end step.

Mana Geyser

Add {R} for each tapped land your opponents control.

Valakut, the Molten Pinnacle

This land enters tapped.
Whenever a Mountain you control enters, if you control at least five other Mountains, you may have this land deal 3 damage to any target.
{T}: Add {R}.

Terrain Generator

{T}: Add {C}.
{2}, {T}: You may put a basic land card from your hand onto the battlefield tapped.

Buster Sword

Equipped creature gets +3/+2.
Whenever equipped creature deals combat damage to a player, draw a card, then you may cast a spell from your hand with mana value less than or equal to that damage without paying its mana cost.
Equip {2}

Crash Through

Creatures you control gain trample until end of turn. (Each of those creature can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.