Sakashima the Impostor

You may have Sakashima the Impostor enter as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step."

Oskar, Rubbish Reclaimer

This spell costs {1} less to cast for each different mana value among cards in your graveyard.
Whenever you discard a nonland card, you may cast it from your graveyard.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Sakashima of a Thousand Faces

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

Cyclonus, Cybertronian Fighter

Living metal (During your turn, this Vehicle is also a creature.)
Flying
Whenever Cyclonus deals combat damage to a player, convert it. If you do, there is an additional beginning phase after this phase. (The beginning phase includes the untap, upkeep, and draw steps.)

Cyclonus, the Saboteur

More Than Meets the Eye {5}{U}{B} (You may cast this card converted for {5}{U}{B}.)
Flying
Whenever Cyclonus deals combat damage to a player, it connives. Then if Cyclonus's power is 5 or greater, convert it. (To have a creature connive, draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

Cyclonus, the Saboteur // Cyclonus, Cybertronian Fighter

Sphinx of the Second Sun

Flying
At the beginning of each of your postcombat main phases, there is an additional beginning phase after this phase. (The beginning phase includes the untap, upkeep, and draw steps.)