30 cards where the text includes “partner” and (the card types include “creature” and the card types include “legendary”) and the colors ≤ RU and the cards can be your commander

Alena, Kessig Trapper (Commander Legends #160)
Amy Pond (Doctor Who #75)
Brallin, Skyshark Rider (Commander 2020 #4)
Breeches, Brazen Plunderer (The Lost Caverns of Ixalan Commander #217)
Brinelin, the Moon Kraken (Commander Masters #78)
Dargo, the Shipwrecker (Commander Legends #172)
Eligeth, Crossroads Augur (Commander Legends #66)
Esior, Wardwing Familiar (Commander Legends #67)
Fluros of Myra's Marvels (Unfinity #46)
Ghost of Ramirez DePietro (The Lost Caverns of Ixalan Commander #157)
Glacian, Powerstone Engineer (Commander Legends #72)
Haldan, Avid Arcanist (Commander 2020 #2)
Ignacio of Myra's Marvels (Unfinity #112)
Jenny Flint (Doctor Who #136)
Kediss, Emberclaw Familiar (Commander Legends #188)
Khorvath Brightflame (Battlebond #9)
Krark, the Thumbless (Commander Legends #189)
Kraum, Ludevic's Opus (Commander 2016 #34)
Laurine, the Diversion (Outlaws of Thunder Junction Commander #172)
Ludevic, Necro-Alchemist (Commander 2016 #37)
Malcolm, Keen-Eyed Navigator (The Lost Caverns of Ixalan Commander #161)
Okaun, Eye of Chaos (Battlebond #6)
Rograkh, Son of Rohgahh (Commander Legends #197)
Sakashima of a Thousand Faces (Commander Legends #89)
Siani, Eye of the Storm (Commander Legends #95)
The Prismatic Piper (Commander Masters #1)
Timin, Youthful Geist (Crimson Vow Commander #16)
Toggo, Goblin Weaponsmith (Commander Legends #204)
Toothy, Imaginary Friend (Battlebond #12)
Zndrsplt, Eye of Wisdom (Battlebond #5)

Though this query has ended, its relics still slumber in New Argive.