This sound effect can be found on Orchestral Colours, which was made by Best Service.
https://soundeffects.fandom.com/wiki/File:69_C_MAJ-stereo.wav https://soundeffects.fandom.com/wiki/File:69_D-sharp_MAJ-stereo.wav https://soundeffects.fandom.com/wiki/File:69_F-sharp_MAJ-stereo.wav https://soundeffects.fandom.com/wiki/File:69_A_MAJ-stereo.wav