The Beleaguered Boxer

If The Snapstone Wielder is your commander and your deck contains no land cards, your starting hand size is four and for the rest of the game, at the beginning of your upkeep, you get a mana counter. During each of your turns, you can spend mana of any color equal to the number of mana counters you have. (You want mana on opponent's turns, you're on your own. Who needs instant-speed interaction—)

Whenever The Snapstone Wielder enters or attacks, cast a random nonland Magic card without paying its mana cost. If it has targets, choose the targets at random.

As long as this creature is your commander, you may play cards from any game in your deck as long as they can be reasonably translated into Magic. They all fit within this Commander's color identity.

: Create one resource of any type. (Mana or otherwise.)

As Rukarumel enters, choose a creature type.

Slivers you control and nontoken creatures you control are the chosen type in addition to their other creature types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

, : Create a 1/1 colorless Sliver creature token.

Flying

When Niv-Mizzet enters, reveal the top ten cards of your library. For each color pair, choose a card that's exactly those colors from among them. Put the chosen cards into your hand and the rest on the bottom of your library in a random order.

Eminence — While The Knight of Commentary is in the command zone or on the battlefield, you are freely allowed to ask people for advice on your game while playing. (This includes nearby players, friends around you, and even people you message on your phone, but it all must be done in a timely fashion, courteously, and without causing large interruptions in other games.)

Legendary creatures you control get +X/+X, where X is the number of legendary creatures you control.

Whenever you cast a legendary spell from your hand, exile cards from the top of your library until you exile a legendary nonland card with lesser mana value. You may cast that card without paying its mana cost. Put the rest on the bottom of your library in a random order.