Transit Mage

When this creature enters, you may search your library for an artifact card with mana value 4 or 5, reveal it, put it into your hand, then shuffle.

Rustvale Bridge

This land enters tapped.
Indestructible
{T}: Add {R} or {W}.

Drossforge Bridge

This land enters tapped.
Indestructible
{T}: Add {B} or {R}.

Enthusiastic Mechanaut

Flying
Artifact spells you cast cost {1} less to cast.

Arcane Signet

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

Thornglint Bridge

This land enters tapped.
Indestructible
{T}: Add {G} or {W}.

Slagwoods Bridge

This land enters tapped.
Indestructible
{T}: Add {R} or {G}.

Ertha Jo, Frontier Mentor

When Ertha Jo enters, create a 1/1 red Mercenary creature token with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."
Whenever you activate an ability that targets a creature or player, copy that ability. You may choose new targets for the copy.

Razortide Bridge

This land enters tapped.
Indestructible
{T}: Add {W} or {U}.

Sunken Palace

This land enters tapped.
{T}: Add {U}.
{1}{U}, {T}, Exile seven cards from your graveyard: Add {U}. When you spend this mana to cast a spell or activate an ability, copy that spell or ability. You may choose new targets for the copy. (Mana abilities can't be copied.)

Gogo, Master of Mimicry

{X}{X}, {T}: Copy target activated or triggered ability you control X times. You may choose new targets for the copies. This ability can't be copied and X can't be 0. (Mana abilities can't be targeted.)

Door to Nothingness

This artifact enters tapped.
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice this artifact: Target player loses the game.

Mistvault Bridge

This land enters tapped.
Indestructible
{T}: Add {U} or {B}.

Loran of the Third Path

Vigilance
When Loran enters, destroy up to one target artifact or enchantment.
{T}: You and target opponent each draw a card.

Goldmire Bridge

This land enters tapped.
Indestructible
{T}: Add {W} or {B}.

Tanglepool Bridge

This land enters tapped.
Indestructible
{T}: Add {G} or {U}.

Adric, Mathematical Genius

{2}{U}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
Ultimate Sacrifice — {1}{U}, Sacrifice Adric: Counter target activated or triggered ability.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Ramos, Dragon Engine

Flying
Whenever you cast a spell, put a +1/+1 counter on Ramos for each of that spell's colors.
Remove five +1/+1 counters from Ramos: Add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}. Activate only once each turn.

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, draw two cards.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Mirage Mirror

{2}: This artifact becomes a copy of target artifact, creature, enchantment, or land until end of turn.