Have

Arcane Signet

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

Plague Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{T}: Add {C}.

Don't Have

Lightning-Core Excavator

{5}, {T}, Sacrifice Lightning-Core Excavator: It deals 3 damage to any target.

Goblin Firebomb

Flash
{7}, {T}, Sacrifice this artifact: Destroy target permanent.

Getting

Market Gnome

When Market Gnome dies, you gain 1 life and draw a card.
When Market Gnome is exiled from the battlefield while you're activating a craft ability, you gain 1 life and draw a card.

Workshop Assistant

When Workshop Assistant dies, return another target artifact card from your graveyard to your hand.

Mirage Mirror

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

Junk Diver

Flying
When Junk Diver dies, return another target artifact card from your graveyard to your hand.

Candy Trail

When Candy Trail enters, scry 2.
{2}, {T}, Sacrifice Candy Trail: You gain 3 life and draw a card.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Gold Myr

Sentinel Totem

When Sentinel Totem enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}, Exile Sentinel Totem: Exile all graveyards.

Iron Apprentice

Iron Apprentice enters with a +1/+1 counter on it.
When Iron Apprentice dies, if it had counters on it, put those counters on target creature you control.

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Inquisitive Puppet

When Inquisitive Puppet enters, scry 1.
Exile Inquisitive Puppet: Create a 1/1 white Human creature token.

Spectrum Sentinel

Protection from multicolored (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything multicolored.)
Whenever a nonbasic land an opponent controls enters, you gain 1 life.

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Marble Diamond

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Oswald Fiddlebender

Magical Tinkering — {W}, {T}, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.

Teshar, Ancestor's Apostle

Flying
Whenever you cast a historic spell, return target creature card with mana value 3 or less from your graveyard to the battlefield. (Artifacts, legendaries, and Sagas are historic.)

Silent Dart

{4}, {T}, Sacrifice Silent Dart: It deals 3 damage to target creature.

Fountain of Renewal

At the beginning of your upkeep, you gain 1 life.
{3}, Sacrifice Fountain of Renewal: Draw a card.

Navigator's Compass

When Navigator's Compass enters, you gain 3 life.
{T}: Until end of turn, target land you control becomes the basic land type of your choice in addition to its other types.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Ninja's Kunai

Equipped creature has "{1}, {T}, Sacrifice Ninja's Kunai: Ninja's Kunai deals 3 damage to any target."
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Filigree Familiar

When Filigree Familiar enters, you gain 2 life.
When Filigree Familiar dies, draw a card.

Cogwork Assembler

{7}: Create a token that's a copy of target artifact. That token gains haste. Exile it at the beginning of the next end step.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Ornithopter of Paradise

Sparring Construct

When Sparring Construct dies, put a +1/+1 counter on target creature you control.

Scrap Trawler

Whenever Scrap Trawler or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.

Mechtitan Core

{5}, Exile Mechtitan Core and four other artifact creatures and/or Vehicles you control: Create Mechtitan, a legendary 10/10 Construct artifact creature token with flying, vigilance, trample, lifelink, and haste that's all colors. When that token leaves the battlefield, return all cards exiled with Mechtitan Core except Mechtitan Core to the battlefield tapped under their owners' control.
Crew 2

Portable Hole

When Portable Hole enters, exile target nonland permanent an opponent controls with mana value 2 or less until Portable Hole leaves the battlefield.

Foundry Inspector

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

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Yotian Frontliner

Whenever Yotian Frontliner attacks, another target creature you control gets +1/+1 until end of turn.
Unearth {W} ({W}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Prism Ring

As Prism Ring enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Jhoira's Familiar

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