Will work with elves. Arboreal Alliance, Mirkwood Elk, and Tyvar Kell are good with elves and great with numerous green commander strategies
Alexios attacks each combat if able, can't be sacrificed, and can't attack its owner
Both of Karn's abilities net card advantage and his minus gives you a sizeable artifact creature as the game goes on
Then, I can tap this artifact at any time to put a creature on the battlefield if it has a mana value equal to the number of charge counters on Aether Vial
As long as you can maintain the monarchy, you're doubling up on value and drawing additional cards at the same time
Second, and even more important, these promos are triggered by playing in a Constructed, Sealed, or Draft tournament