Decided to figure out how to make SoundFonts, and a pile of toy keyboards I have laying around has been a good place to start.

http://shiru.untergrund.net/files/sf2/ss-326.zip
http://shiru.untergrund.net/files/sf2/cyber_piano.zip
http://shiru.untergrund.net/files/sf2/bf-630.zip - chippy
http://shiru.untergrund.net/files/sf2/hs-3230.zip - MOD-like
http://shiru.untergrund.net/files/sf2/tx-5488a.zip - chippy

the TX-5488A sounds like some of the old DSI toys Inc Kawasaki toy keyboards I have. software wise I think it is the same as my QM-3758 toy keyboard (5 demo songs) (short jingle is played on preset sound buttons)

Thank you for the information. You're very helpful.

Are those the names of the toy pianos you used or are they .sf2 files torn out of them?
Do toy pianos even use .sf2 files???

I love that you included photos of each keyboard too. Can't wait to try them out!