Underhanded Designs

Whenever an artifact you control enters, you may pay {1}. If you do, each opponent loses 1 life and you gain 1 life.
{1}{B}, Sacrifice this enchantment: Destroy target creature. Activate only if you control two or more artifacts.

Bloodsoaked Champion

This creature can't block.
Raid — {1}{B}: Return this card from your graveyard to the battlefield. Activate only if you attacked this turn.

Haunt of the Dead Marshes

When this creature enters, scry 1.
{2}{B}: Return this card from your graveyard to the battlefield tapped. Activate only if you control a legendary creature.

Eater of Virtue

Whenever equipped creature dies, exile it.
Equipped creature gets +2/+0.
As long as a card exiled with Eater of Virtue has flying, equipped creature has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.
Equip {1}

Swamp

Junk Diver

Flying
When this creature dies, return another target artifact card from your graveyard to your hand.

Su-Chi Cave Guard

Vigilance
Ward {4} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)
When this creature dies, add eight {C}. Until end of turn, you don't lose this mana as steps and phases end.

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Ashnod, Flesh Mechanist

Deathtouch
Whenever Ashnod attacks, you may sacrifice another creature. If you do, create a tapped Powerstone token.
{5}, Exile a creature card from your graveyard: Create a tapped 3/3 colorless Zombie artifact creature token.

Thran Spider

Reach
When this creature enters, you and target opponent each create a tapped Powerstone token.
{7}: Look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Wurmcoil Larva

Deathtouch, lifelink
When this creature dies, create a 1/2 black Phyrexian Wurm artifact creature token with deathtouch and a 2/1 black Phyrexian Wurm artifact creature token with lifelink.

Grim Haruspex

Morph {B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
Whenever another nontoken creature you control dies, draw a card.

Mold Folk

Lifelink
Mold Harvest — {1}, Sacrifice another creature or an artifact: Put a +1/+1 counter on this creature.

Endless Cockroaches

When this creature dies, return it to its owner's hand.

Marionette Master

Fabricate 3 (When this creature enters, put three +1/+1 counters on it or create three 1/1 colorless Servo artifact creature tokens.)
Whenever an artifact you control is put into a graveyard from the battlefield, target opponent loses life equal to this creature's power.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Karn, Living Legacy

+1: Create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")
−1: Pay any amount of mana. Look at that many cards from the top of your library, then put one of those cards into your hand and the rest on the bottom of your library in a random order.
−7: You get an emblem with "Tap an untapped artifact you control: This emblem deals 1 damage to any target."

Zulaport Cutthroat

Whenever this creature or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Skullport Merchant

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
{1}{B}, Sacrifice another creature or a Treasure: Draw a card.

Retrofitted Transmogrant

{3}{B}: Return this card from your graveyard to the battlefield tapped with two +1/+1 counters on it.

Myr Retriever

When this creature dies, return another target artifact card from your graveyard to your hand.

Monumental Corruption

Target player draws X cards and loses X life, where X is the number of artifacts you control.

Workshop Assistant

Vito's Inquisitor

{B}, Sacrifice another creature or artifact: Put a +1/+1 counter on this creature. It gains menace until end of turn.

Abnormal Endurance

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Scrap Trawler

Whenever this creature dies 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.

Battle at the Bridge

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Target creature gets -X/-X until end of turn. You gain X life.

Pitiless Carnage

Sacrifice any number of permanents you control, then draw that many cards.
Plot {1}{B}{B} (You may pay {1}{B}{B} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Case of the Stashed Skeleton

When this Case enters, create a 2/1 black Skeleton creature token and suspect it. (It has menace and can't block.)
To solve — You control no suspected Skeletons. (If unsolved, solve at the beginning of your end step.)
Solved — {1}{B}, Sacrifice this Case: Search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.

Terisiare's Devastation

You lose X life and create X tapped Powerstone tokens. Then all creatures get -1/-1 until end of turn for each artifact you control. (The tokens are artifacts with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Trading Post

{1}, {T}, Discard a card: You gain 4 life.
{1}, {T}, Pay 1 life: Create a 0/1 white Goat creature token.
{1}, {T}, Sacrifice a creature: Return target artifact card from your graveyard to your hand.
{1}, {T}, Sacrifice an artifact: Draw a card.

Night's Whisper

Steel Hellkite

Flying
{2}: This creature gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by this creature this turn. Activate only once each turn.

Powerstone Fracture

As an additional cost to cast this spell, sacrifice an artifact or creature.
Destroy target creature or planeswalker.

Persistent Specimen

{2}{B}: Return this card from your graveyard to the battlefield tapped.

Marionette Apprentice

Fabricate 1 (When this creature enters, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)
Whenever another creature or artifact you control is put into a graveyard from the battlefield, each opponent loses 1 life.

Myr Sire

When this creature dies, create a 1/1 colorless Phyrexian Myr artifact creature token.

Sivriss, Nightmare Speaker

{T}, Sacrifice another creature or an artifact: For each opponent, you mill a card, then return that card from your graveyard to your hand unless that player pays 3 life. (To mill a card, put the top card of your library into your graveyard.)
Choose a Background (You can have a Background as a second commander.)

Acolyte of Aclazotz

{T}, Sacrifice another creature or artifact: Each opponent loses 1 life and you gain 1 life.

Lobelia, Defender of Bag End

When Lobelia enters, look at the top card of each opponent's library and exile those cards face down.
{T}, Sacrifice an artifact: Choose one —
• Until end of turn, you may play a card exiled with Lobelia without paying its mana cost.
• Each opponent loses 2 life and you gain 2 life.

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.

Resurrection Orb

Equipped creature has lifelink.
Whenever equipped creature dies, return that card to the battlefield under its owner's control at the beginning of the next end step.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Popular Egotist

{1}{B}, Sacrifice another creature or enchantment: This creature gains indestructible until end of turn. Tap it. (Damage and effects that say "destroy" don't destroy it.)
Whenever you sacrifice a permanent, target opponent loses 1 life and you gain 1 life.

Thought Vessel

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

Mycosynth Wellspring

When this artifact enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Clay Revenant

This creature enters tapped.
{2}{B}: Return this card from your graveyard to your hand.

Transmutation Font

{T}: Create your choice of a Blood token, a Clue token, or a Food token.
{3}, {T}, Sacrifice three artifact tokens with different names: Search your library for an artifact card, put it onto the battlefield, then shuffle. Activate only as a sorcery.

Transmogrant Altar

{B}, {T}, Sacrifice a creature: Add {C}{C}{C}.
{2}, {T}, Sacrifice a creature: Create a 3/3 colorless Zombie artifact creature token. Activate only as a sorcery.

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice this artifact: Create a 10/10 colorless Eldrazi creature token.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Demonic Vigor

Enchant creature
Enchanted creature gets +1/+1.
When enchanted creature dies, return that card to its owner's hand.

Agent of the Shadow Thieves

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, put a +1/+1 counter on this creature. It gains deathtouch and indestructible until end of turn."

Herald of Anguish

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Flying
At the beginning of your end step, each opponent discards a card.
{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Kuldotha Forgemaster

{T}, Sacrifice three artifacts: Search your library for an artifact card, put it onto the battlefield, then shuffle.

Clattering Augur

This creature can't block.
When this creature enters, you draw a card and you lose 1 life.
{2}{B}{B}: Return this card from your graveyard to your hand.

Myriad Landscape

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Ichor Wellspring

When this artifact enters or is put into a graveyard from the battlefield, draw a card.

Transmogrant's Crown

Equipped creature gets +2/+0.
Whenever equipped creature dies, draw a card.
Equip {2} or {B}

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Wurmcoil Engine

Deathtouch, lifelink
When this creature dies, create a 3/3 colorless Phyrexian Wurm artifact creature token with deathtouch and a 3/3 colorless Phyrexian Wurm artifact creature token with lifelink.

Razorlash Transmogrant

This creature can't block.
{4}{B}{B}: Return this card from your graveyard to the battlefield with a +1/+1 counter on it. This ability costs {4} less to activate if an opponent controls four or more nonbasic lands.

Supernatural Stamina

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}

Undying Malice

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Bladed Pinions

Equipped creature has flying and first strike.
Equip {2}

Kaldra Compleat

Living weapon
Indestructible
Equipped creature gets +5/+5 and has first strike, trample, indestructible, haste, and "Whenever this creature deals combat damage to a creature, exile that creature."
Equip {7}

Chariot of Victory

Equipped creature has first strike, trample, and haste.
Equip {1}

Agent of the Iron Throne

Commander creatures you own have "Whenever an artifact or creature you control is put into a graveyard from the battlefield, each opponent loses 1 life."

Lich-Knights' Conquest

Sacrifice any number of artifacts, enchantments, and/or tokens. Return that many creature cards from your graveyard to the battlefield.

Sharpened Pitchfork

Equipped creature has first strike.
As long as equipped creature is a Human, it gets +1/+1.
Equip {1}

Cult Conscript

This creature enters tapped.
{1}{B}: Return this card from your graveyard to the battlefield. Activate only if a non-Skeleton creature died under your control this turn.

Threefold Thunderhulk

This creature enters with three +1/+1 counters on it.
Whenever this creature enters or attacks, create a number of 1/1 colorless Gnome artifact creature tokens equal to its power.
{2}, Sacrifice another artifact: Put a +1/+1 counter on this creature.