One frontrunner is certainly Endurance, which is great against decks trying to exploit their graveyard
Fate Reforged (2015) brought us Outpost Siege, which served mostly as a sideboard card, but also had combopotential with the second option
It doesn't copy whether Ran and Shaw are tapped or untapped, whether they have any counters on them or Auras or Equipment attached to them, or any non-copy effects that have changed their power, toughness, types, color, or so on
and Sigarda, Heron's Grace Selesnya Humans provide several important traits that can help you excel within the Commander format
It draws you cards two different ways: 1) whenever you get attacked by two or more creatures 2) whenever an opponent casts their second spell each turn
Leonardo is the perfect way to cheat expensive artifacts into play, and gives you a built-in win condition by buffing those Thopter tokens massively if you can swing in with a full hand