Julian's Snack Stash

 This artifact enters with a first strike counter for each R spent to cast it, a lifelink counter for each W spent to cast it, and a flying counter for each U spent to cast it.
Whenever a creature you control enters, you may move a counter from this artifact onto that creature. 
2, T,   Sacrifice this artifact: You gain 3 life.

Raven, Forsaken of Power

Flying
Whenever this creature deals combat damage to a player, if that player has more lands than you, deal damage equal to the difference to each creature they control

Mikey's Umbrella

When this Equipment enters, attach it to target creature you control. 
Equipped creature gets +1/+3 and has flying and vigilance
Equip 2

Raven's Effigy of Spite

All lands gain “When this land enters the battlefield, it deals 1 damage to its controller.” This also is given to lands that aren’t on the battlefield.
4RG, T, Sacrifice this artifact: Each opponent loses life equal to the amount of non basic lands they control.

Jakob, Armored Avenger

Menace
Bushido 3 (Whenever this creature blocks or becomes blocked, it gets +3/+3 until end of turn.)
Ward—Pay 3 Life  (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 3 Life .)
This creature gains +1/+0 for each creature in exile

Jakob, Crazed Inventor

R, T: Exile the top card of your library. Until the end of your turn, you may play that card.
3RWB: Transform Jacob. Activate only if there are 4 or more creatures you own in exile and only as a sorcery.

Jakob, Crazed Inventor // Jakob, Armored Avenger

Cayth, Famed Mechanist

Fabricate 1 (When this creature enters, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)
Other nontoken creatures you control have fabricate 1.
{2}, {T}: Choose one —
• Populate.
• Proliferate.

Mikey, Cobalt Crusader

Defender, Lifelink, Flying
{1},Sacrifice a Treasure: Roll a d4
1 - Put a +1/+1 counter on this creature
2 - Put a +1/+1 counter on up to two other creatures you control
3 - Put a shield counter on target creature you control. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
4 - Add two mana of any colour to your mana pool

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

C.A.M.P.

Whenever fortified land is tapped for mana, put a +1/+1 counter on target creature you control. If that creature shares a color with the mana that land produced, create a Junk token. (It's an artifact with "{T}, Sacrifice this token: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
Fortify {3} ({3}: Attach to target land you control. Fortify only as a sorcery.)

Ashnod's Altar

Bootleggers' Stash

Lands you control have "{T}: Create a Treasure token."

Takim, Calculating General

Vigilance
Whenever you sacrifice one or more nontoken creatures, draw a card. This ability can only trigger once a turn.
B, T, : Target opponent loses X life, where X is the number of creatures that died last turn.

Raggadragga, Goreguts Boss

Each creature you control with a mana ability gets +2/+2.
Whenever a creature you control with a mana ability attacks, untap it.
Whenever you cast a spell, if at least seven mana was spent to cast it, untap target creature. It gets +7/+7 and gains trample until end of turn.

Fire Lord Zuko

Firebending X, where X is Fire Lord Zuko's power. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)
Whenever you cast a spell from exile and whenever a permanent you control enters from exile, put a +1/+1 counter on each creature you control.

Mr. Foxglove

Lifelink
Whenever Mr. Foxglove attacks, draw cards equal to the number of cards in defending player's hand minus the number of cards in your hand. If you didn't draw cards this way, you may put a creature card from your hand onto the battlefield.

Insight Engine

{2}, {T}: Put a charge counter on this artifact, then draw a card for each charge counter on it.

Marneus Calgar

Double strike
Master Tactician — Whenever one or more tokens you control enter, draw a card.
Chapter Master — {6}: Create two 2/2 white Astartes Warrior creature tokens with vigilance.

Julian, Social Butterfly

Flying
Alliance — Whenever another creature enters under your control, choose one that hasn’t been chosen this turn — 
• Exile the top of your library, you may play it this turn
• Put a stun counter on target creature
• Put a +1/+1 counter on target creature you control

Takim's Codex

This artifact enters with X page counters. 
Whenever a creature you control dies during an opponent’s turn, remove a page counter and draw a card.
B, Sacrifice this artifact: Return target creature with mana value equal to the number of page counters on this artifact. Activate only as a sorcery

Jakob's Workbench

Whenever fortified land is tapped for mana, exile the top card of your library. You may play it this turn.
Fortify 3 (3: Attach to target land you control. Fortify only as a sorcery.)