Ideally you want to be at four or five such cards (in a forty card list) but you can easily get away with less if you just play buff cards to empower your tokens or you play tutor, filter and recursion to ensure you have access to the few you do have
I realize that nobody plays Serra Angel anymore, but for those new to the game, you'll have to take my word that she was quite the beater back in "the day." Each of the cards will be listed in descending order, from number fifty to glorious number one
Using this card in play is optimal
This is partly because Sorin is the only legendary creature that offers Extort, but the card also comes down early, setting up your life drain engine quickly

Sakashima the Impostor (for flavor with the "clone tribal" theme) Zur the Enchanter (much like in Modern, having a tutorable clone is very powerful) Rayne, Academy Chancellor and Hakim, Loreweaver (where Mirrorweave can be a copy of the best aura enchanting your commander) Estrid, the Masked (enchantress) Angus Mackenzie (where two Ghostly Prisons or Propagandas are better than one) Zedruu the Greathearted (where Mirrormade can copy something Donateable to give to your opponent for card advantage) Teferi, Temporal Archmage (where Mirrormade can replace Copy Artifact as part of the Isochron Scepter + Dramatic Reversal combo, where the main plan is to get Dramatic Reversal under Isochron Scepter to get infinite untaps of non-land permanents and then use Mirrormade to copy Isochron Scepter and imprint something that actually ends the game, with Swan Song being a popular meme-ish choice)
My youngest was an apple juice addict, and I couldn't keep up with his habit