I'm going to just go through the original partners in alphabetical order and explain what new partner I'd try to pair up with it
This time around, we're adding Azami, Lady of Scrolls, Teferi, Mage of Zhalfir, and Tivit, Seller of Secrets to the control line-up
Gandalf the WhiteGandalf the White While Gandalf does work with legendary permanents, most of the decks that he helms are themed around artifacts
Uncommons Armored Scrapgorger Evolving Adaptive Tyvar's Stand Drown in Ichor Sheoldred's Edict Rares Bloated Contaminator Venerated Rotpriest Skrelv's Hive Copperline Gorge Skrelv, Defector Mite Mythic Rares Vraska, Betrayal's Sting Mondrak, Glory Dominus Phyrexian Obliterator Nissa, Ascended Animist Tyrranax Rex Phyrexia: All Will Be One Is Here Now that you have some (preliminary) tools to match your talent, your next step might be to jump into the Standard Metagame Challenge, February 1013, and test yourself while claiming rewards for your well-planned strategies