As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Copy target instant or sorcery spell. You may choose new targets for the copy.

: Add .

Equipped creature gets +1/+0.
When equipped creature deals combat damage to a player, unattach Elbrus, then transform it.
Equip

Vigilance
Whenever you cast a spell, creatures you control get +1/+0 until end of turn. Scry 1.
When Gandalf dies, you may put it into its owner's library fifth from the top.

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Whenever a player taps a land for mana, this enchantment deals 1 damage to that player.

When this enchantment enters, you draw four cards and you lose 4 life.
At the beginning of your upkeep, if you control four or more Demons with different names, you win the game.

Whenever one or more creatures you control deal combat damage to a player, tap all lands that player controls and untap all lands you control.

Flying, lifelink
Creature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a creature spell pays for or one mana of that creature's color.)
At the beginning of your first main phase, you may pay . If you do, transform Eirdu.

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip (: Attach to target creature you control. Equip only as a sorcery.)

: Add one mana of any color in your commander's color identity.

When this enchantment enters, you become the monarch.
At the beginning of your upkeep, create a 1/1 white Spirit creature token with flying. If you're the monarch, create a 4/4 white Angel creature token with flying instead.

Other Goblins get +1/+1 and have mountainwalk.

This land enters tapped unless you control a Mountain or a Forest.
: Add or .

Double strike
When this creature enters, it deals 4 damage divided as you choose among any number of target creatures and/or planeswalkers.
Evoke—Exile a red card from your hand.

Menace
Whenever Black Widow deals combat damage to a player, that player exiles cards from the top of their library until they exile a nonland card. You may put a +1/+1 counter on Black Widow. If you don't, you may cast the exiled nonland card until end of turn and mana of any type can be spent to cast that spell.

Whenever a black card is put into an opponent's graveyard from anywhere, you may draw a card.

When Ezuri enters, you may pay . If you do, proliferate twice.
Whenever you proliferate, draw a card.