Yunyun appears in the main plaza when Miiverse isn't connected.
Wii Party U
In Wii Party U, Yunyun is a Beginner difficulty Mii.
Mario Kart Tour
The name of Yunyun can appear as opponent names like other Wii Sports Club Miis. Since the Mii Tour in 2022, she is one of the default Mii drivers available to choose from.
Super Mario Bros. Wonder
Yunyun appears in the online play guide of Super Mario Bros. Wonder. In the guide, you can see the friend whose name is "Yunyun" and user icon is her Mii.