Tezzeret the Schemer

Oracle Text
+1: Create a colorless artifact token named Etherium Cell with "
, Sacrifice this artifact: Add one mana of any color."−2: Target creature gets +X/-X until end of turn, where X is the number of artifacts you control.
−7: You get an emblem with "At the beginning of combat on your turn, target artifact you control becomes an artifact creature with base power and toughness 5/5."
Card Rulings
2/9/2017 The value of X for Tezzeret’s second ability is determined only as the ability resolves. It won’t change later in the turn if the number of artifacts you control changes.
2/9/2017 The effect of the emblem’s triggered ability lasts indefinitely.
2/9/2017 An artifact that becomes a creature due to the emblem’s ability can’t attack unless you’ve controlled it continuously since your turn began. It doesn’t matter whether or not it was a creature at that time.
2/9/2017 An artifact creature targeted by the emblem’s ability becomes 5/5 instead of its normal power and toughness.
2/9/2017 A Vehicle targeted by the emblem’s ability becomes a 5/5 creature. Crewing it won’t change its power and toughness.
2/9/2017 If an Equipment becomes a creature, it becomes unattached and it can’t be attached to a creature.
As not only can he start turning your worthless mana rocks into 5/5s permanently, he makes mana acceleration in a color that rarely gets it.
If you are playing to the strengths of an artifact deck you can easily have him act as spot-removal against enemy creatures as for instance a +5/-5 isn't hard t achieve but you know what is also really cool about his minus ability? He can buff your creatures. Tell me I'm not the only who thought to themselves: "Hey with 10 artifacts I can buff my blightsteel colossus into a 21/1 indestructible trampler with infect that requires at least 12 toughness worth of creatures to be stopped from killing some with poison."
And before you say it, getting 10 artifacts on the board is just child's play especially if anyone here has seen EDH where not only could you make everything you and your opponent's control into artifacts but you can: Steal them, Exile them, satisfy a "you win the game" card, force tempo loss onto your opponent as you bounce their entire board back to their hand and oh so much more.
As me personally? Maybe I'm just not looking at him through a Standard lens and see his potential outside of it and even within it.