Debuting in Commander 2015 on the card Broodbirth Viper, this ability allows the creature that hosts the ability to duplicate itself and attack each other player in your Commander pod
For example, if you know how to use crew cards effectively, you can still pilot your Vehicles with ease
For just one black mana, you get a whole new hand of cards - that's absurd
It lets you form a plan, it lets you play around their stuff while setting up your own nicely
Creatures (30) 2 Meddling Mage 1 Venser, Shaper Savant 1 Kitchen Finks 4 Flickerwisp 4 Leonin Arbiter 1 Mirran Crusader 1 Phyrexian Metamorph 2 Blade Splicer 1 Fiend Hunter 3 Thalia, Guardian of Thraben 3 Restoration Angel 1 Lyev Skyknight 1 Lavinia of the Tenth 3 Reflector Mage 2 Eldrazi Displacer Lands (22) Spells (8) That version had real mana issues and a fair few flex spots, as well as an undesirable weakness to both Blood Moon and our own Leonin Arbiters
Bonus Tip: When youre building a deck for a Constructed format like Standard or Modern, as well as the 60 main deck cards, you can have an additional 15 cards in your sideboard (if you use one)