Arcane Signet

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Simic Signet

Sol Ring

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Golgari Signet

Crackdown Construct

Whenever you activate an ability of an artifact or creature that isn't a mana ability, Crackdown Construct gets +1/+1 until end of turn.

Swamp

Mountain

Rakdos Signet

Forest

Command Tower

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Plains

Island

Izzet Signet

Composite Golem

Sacrifice Composite Golem: Add {W}{U}{B}{R}{G}.

Gruul Signet

Azorius Signet

Orzhov Signet

Dimir Signet

Selesnya Signet

Kenrith, the Returned King

{R}: All creatures gain trample and haste until end of turn.
{1}{G}: Put a +1/+1 counter on target creature.
{2}{W}: Target player gains 5 life.
{3}{U}: Target player draws a card.
{4}{B}: Put target creature card from a graveyard onto the battlefield under its owner's control.