Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on Replicating Ring. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

Hokori, Dust Drinker

Lands don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player untaps a land they control.

Arcane Signet

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

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Crawlspace

No more than two creatures can attack you each combat.

Sol Ring

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.