Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Rocco, Street Chef

At the beginning of your end step, each player exiles the top card of their library. Until your next end step, each player may play the card they exiled this way.
Whenever a player plays a land from exile or casts a spell from exile, you put a +1/+1 counter on target creature and create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Descent into Avernus

At the beginning of your upkeep, put two descent counters on this enchantment. Then each player creates X Treasure tokens and this enchantment deals X damage to each player, where X is the number of descent counters on this enchantment.

Kibo, Uktabi Prince

{T}: Each player creates a colorless artifact token named Banana with "{T}, Sacrifice this token: Add {R} or {G}. You gain 2 life."
Whenever an artifact an opponent controls is put into a graveyard from the battlefield, put a +1/+1 counter on each creature you control that's an Ape or a Monkey.
Whenever Kibo attacks, defending player sacrifices an artifact of their choice.

Minimus Containment

Enchant nonland permanent
Enchanted permanent is a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color," and it loses all other abilities. (If it was a creature, it's no longer a creature.)

Breya's Apprentice

When this creature enters, create a 1/1 colorless Thopter artifact creature token with flying.
{T}, Sacrifice an artifact: Choose one —
• Exile the top card of your library. Until the end of your next turn, you may play that card.
• Target creature gets +2/+0 until end of turn.

Goblin Bombardment

Sacrifice a creature: This enchantment deals 1 damage to any target.

Tempting Contract

At the beginning of your upkeep, each opponent may create a Treasure token. For each opponent who does, you create a Treasure token.

Jaheira, Friend of the Forest

Tokens you control have "{T}: Add {G}."
Choose a Background (You can have a Background as a second commander.)

Osgir, the Reconstructor

Vigilance
{1}, Sacrifice an artifact: Target creature you control gets +2/+0 until end of turn.
{X}, {T}, Exile an artifact card with mana value X from your graveyard: Create two tokens that are copies of the exiled card. Activate only as a sorcery.

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)