This thing can tap for any color of mana, arrives untapped and can tap for three mana to sacrifice a dork and gain 2 life (well, it's toughness, which might be 1 with a Bloodghast or Blood Artist or more with the Launderer)
Creature - Goblin Color tag templates(None) Siege-Gang Lieutenant Lieutenant At the beginning of combat on your turn, if you control your commander, create two 1/1 red Goblin creature tokens
For the purposes of this list Ill be looking at base versions of cards, so no alt-arts or special treatments in the main list (Ill touch on them at the end, though)
Its a 4-drop, but it has ward and I can see things really getting crazy
Greens ability to ramp will make the mana cost not much of a problem, and the loyalty abilities are the bomb
The list of Game Changers includes 40 cards that have a huge impact both in Commander and the kind of game you're playing