Echoes of Eternity

If a triggered ability of a colorless spell you control or another colorless permanent you control triggers, that ability triggers an additional time.
Whenever you cast a colorless spell, copy it. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Urza's Cave

{T}: Add {C}.
{3}, {T}, Sacrifice Urza's Cave: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Myr Galvanizer

Other Myr creatures you control get +1/+1.
{1}, {T}: Untap each other Myr you control.

Forsaken Monument

Colorless creatures you control get +2/+2.
Whenever you tap a permanent for {C}, add an additional {C}.
Whenever you cast a colorless spell, you gain 2 life.

Glaring Fleshraker

Whenever you cast a colorless spell, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."
Whenever another colorless creature you control enters, Glaring Fleshraker deals 1 damage to each opponent.

Ormendahl, Profane Prince

Westvale Abbey

{T}: Add {C}.
{5}, {T}, Pay 1 life: Create a 1/1 white and black Human Cleric creature token.
{5}, {T}, Sacrifice five creatures: Transform Westvale Abbey, then untap it.

Westvale Abbey // Ormendahl, Profane Prince

Eldrazi Monument

Creatures you control get +1/+1 and have flying and indestructible.
At the beginning of your upkeep, sacrifice a creature. If you can't, sacrifice Eldrazi Monument.

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Buried Ruin: Return target artifact card from your graveyard to your hand.

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

All Is Dust

Each player sacrifices all permanents they control that are one or more colors.

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Leaden Myr

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

Construct

This creature gets +1/+1 for each artifact you control.

Palladium Myr

Eldrazi Spawn

Dismember

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Myr Propagator

{3}, {T}: Create a token that's a copy of Myr Propagator.

Swamp

Myr Servitor

At the beginning of your upkeep, if Myr Servitor is on the battlefield, each player returns all cards named Myr Servitor from their graveyard to the battlefield.

Myr Superion

Spend only mana produced by creatures to cast this spell.

Copy

(This token can be used to represent a token that's a copy of a permanent.)

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Myr Reservoir

{T}: Add {C}{C}. Spend this mana only to cast Myr spells or activate abilities of Myr.
{3}, {T}: Return target Myr card from your graveyard to your hand.

Human Cleric

Myr Turbine

{T}: Create a 1/1 colorless Myr artifact creature token.
{T}, Tap five untapped Myr you control: Search your library for a Myr creature card, put it onto the battlefield, then shuffle.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Myr Battlesphere

When Myr Battlesphere enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever Myr Battlesphere attacks, you may tap X untapped Myr you control. If you do, Myr Battlesphere gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Myr Matrix

Indestructible (Effects that say "destroy" don't destroy this artifact.)
Myr creatures get +1/+1.
{5}: Create a 1/1 colorless Myr artifact creature token.