Buy Push button PCB 9mm black at the right price @ Electrokit
GitHub - JRodrigoTech/GameBoy-DMG-Button-PCB: Game Boy DMG button adapter PCB board with: D-Pad, Select, Start, A and B (with extra X Y buttons for Mods like GB Zero).
Push button Switches – RJS Electronics Ltd
What's Switch? PCB Switch, and Advantages? | MADPCB