42 cards where the illustration contains “unicorn” and it’s legal in Commander and the colors ≤ GW

Adarkar Unicorn (Ice Age #1)
Benevolent Unicorn (Mirage #4)
Blessed Sanctuary (Jumpstart #1)
Brightmare (Jumpstart #2)
Capashen Unicorn (Invasion #10)
Captivating Unicorn (Theros Beyond Death #6)
Celestial Unicorn (Adventures in the Forgotten Realms #5)
Circle of Dreams Druid (Adventures in the Forgotten Realms #176)
Daybreak Charger (Core Set 2021 #14)
Distinguished Conjurer (Modern Horizons 3 #264)
Emiel the Blessed (Double Masters 2022 #10)
Good-Fortune Unicorn (March of the Machine Commander #326)
Honored Heirloom (Innistrad: Crimson Vow #257)
Inspiring Unicorn (Jumpstart #112)
Lathiel, the Bounteous Dawn (Commander Legends #285)
Life's Legacy (New Capenna Commander #300)
Lonesome Unicorn // Rider in Need (Throne of Eldraine #21)
Loyal Unicorn (Commander Masters #40)
Majestic Auricorn (Ikoria: Lair of Behemoths #22)
Master Decoy (Tempest Remastered #18)
Mesa Unicorn (Jumpstart #122)
Neighborhood Guardian (Murders at Karlov Manor #26)
Noble Quarry (Commander 2015 #193)
Nyxborn Unicorn (Modern Horizons 3 #37)
Opaline Unicorn (Conspiracy: Take the Crown #213)
Order of Leitbur (Fallen Empires #16b)
Pearled Unicorn (Fifth Edition #50)
Plains (Jumpstart #41)
Prized Unicorn (Core Set 2020 #342)
Regal Bunnicorn (Wilds of Eldraine #25)
Regal Unicorn (Classic Sixth Edition #35)
Revered Unicorn (Weatherlight #23)
Ronom Unicorn (Forgotten Realms Commander #71)
Seraphic Steed (Outlaws of Thunder Junction #232)
Steadfast Unicorn (Commander Legends: Battle for Baldur's Gate #44)
Stonewood Invocation (Time Spiral #223)
Sylvan Shepherd (Adventures in the Forgotten Realms #206)
The Princess Takes Flight (Wilds of Eldraine #23)
Valorous Steed (Core Set 2021 #42)
Wishmonger (Mercadian Masques #57)
Zebra Unicorn (Mirage #290)
Zhalfirin Decoy (Modern Horizons #39)

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