I think it’s all the Switch games, or most of them. It’s part of the system font. It’s at least any game that can be played with a single joy-con because the traditional layout doesn’t match the labels in that configuration.

Nintendo is generally good at this part of design. Back in the GameCube days, all the buttons were different shapes, sizes and were easy to tell apart by feel, so they just used icons of the buttons. In the N64 days, X, Y and Z were all triggers in different positions, and the C buttons had arrows on them so you could tell by the icon which was which.