17 cards where the number of colors > 2 and the card types include “planeswalker”

Dihada, Binder of Wills (Dominaria United Commander #1)
Nicol Bolas, Dragon-God (Ravnica Remastered #205)
Nicol Bolas, God-Pharaoh (Double Masters 2022 #260)
Aminatou, the Fateshifter (Double Masters 2022 #169)
Tamiyo, Field Researcher (Eldritch Moon #190)
Nicol Bolas, the Ravager // Nicol Bolas, the Arisen (Core Set 2019 #218)
Nicol Bolas, the Ravager // Nicol Bolas, the Arisen (Core Set 2019 #218)
Sarkhan Unbroken (Dragons of Tarkir #230)
Lord Windgrace (Commander 2018 #43)
Narset of the Ancient Way (Commander Masters #930)
Nicol Bolas, Planeswalker (Archenemy: Nicol Bolas #85)
Geyadrone Dihada (Modern Horizons 2 #199)
Dakkon, Shadow Slayer (Modern Horizons 2 #192)
Jared Carthalion (Dominaria United Commander #2)
Commodore Guff (Commander Masters #706)
Estrid, the Masked (Commander 2018 #40)
Nicol Bolas, the Deceiver (Hour of Devastation #205)
Urza, Academy Headmaster (Unstable #136)

This search is finished. Now the real work can begin.