Typically however you want your top end at 7 and 8 if you want casting them as a backup (which the green based cheat in decks generally do)
They buy Pokmon cards that you no longer need and have a buy list on their site that will tell you exactly what they are accepting and how much they will pay you for it
If you do, switch your Active Pokmon with 1 of your Benched Pokmon
This means you could drop a land and a few Mox, then trade your hand in for a brand new one on your first turn, and leaving your opponent with a potentially bad hand.
Milling five cards and reviving a creature for just five mana is impressive enough, but with the Demonstrate mechanic, it can really shake things up in Commander
Given that Vivi Ornitier was banned in Magic: the Gathering's Standard format more than a month ago, you may have thought that you had seen the last of the small but mighty spellcaster