Another broken combo from 5D and none of the cards needed are restricted.
Turn 1: Mishra's Workshop Tap Metalworker
Turn 2: Staff of dominance GG
Draw your deck, infinate mana you name it!
This is assuming your opening hand+ a draw contains all three of those and at least 3 additional artifacts, your opponent has no counters or Duress effects, etc. This '2 card combo' is one to take with a grain of salt. In reality you need a really good hand in a really artifact heavy deck for it.
Just my $.02
-Dan