And if the Pirate deck has enough legendary creatures in it, then Hero's Blade is a strong option, equipping itself for free onto legendary creatures and giving them +3/+2 (a fine reprint from the Khans of Tarkir block).
One of the wildest cards you can play in this deck is Eldrazi Conscription, giving two of your creatures +10/+10, trample, and the absurdly powerful annihilator 2
17 Aesi, Tyrant Of Gyre Strait Pure Value One of the reasons that Simic is viewed as such a powerful color combination in Commander is that card draw and mana ramp are both integral parts of the format, with blue and green excelling in those areas, respectively
Ratchet, Rescue Racer Color Indicator: White Legendary Artifact Vehicle Living metal (During your turn, this Vehicle is also a creature.) Lifelink Whenever one or more nontoken artifacts you control are put into a graveyard from the battlefield, convert Ratchet
There's also what Wizards refers to internally as ' snap-on equipment .' This isn't a named mechanic, but rather refers to the type of equipment that automatically attaches to creatures once it enters the battlefield, like Embercleave or Mithril Coat