You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities. The "legend rule" doesn't apply to permanents you control. Partner (You can have two commanders if both have partner.)

Whenever a spell you control causes you to gain card advantage, each opponent loses 2 life. (You gain card advantage each time a spell you control resolves and you end up having more cards relative to your opponents than before that spell resolved. Divination, Annihilate, and Wrath of God can all be card advantage. And remember: tokens aren't cards!)

Flying Commander spells you cast have demonstrate. (When you cast a commander spell, you may copy it. If you do, choose an opponent to also copy it. The copies become tokens.) The "legend rule" doesn't apply to commanders you control.

Choose two colors. Add a mana of each of the chosen colors. At the beginning of your next upkeep, pay one mana of each of the chosen colors. If you don't, you lose the game.

Counter target noncreature spell. Whenever an opponent casts a spell named Sol Ring, if Ring Out is in your library, you may search you library for Ring Out, and cast it without paying its mana cost targeting that Sol Ring, then shuffle.

{T}: Add one mana of any color in your commander's color identity. If you control a Command Tower and a Command Power Plant, add two mana of any color in your commander's color identity instead.

{T}: Add one mana of any color in your commander's color identity. If you control a Command Tower and a Command Mine, add two mana of any color in your commander's color identity instead. Command Towers you control have, "{T}: If you control a Command Mine and a Command Power Plant, add three mana of any color in your commander's color identity."