This replacement toaster button is for a Black & Decker "toast-it-all" toaster. It has an internal wedge notch to catch the metal tab of the toaster. This was designed with TinkerCad and the file has been made public so that you can modify it for your needs.
https://www.tinkercad.com/things/2SPrsbCx8vd

Print instructions

The included gcode file was done with 0.3 mm resolution and a 20% infill using PLA.