The tunes over here are taken from: true-piano-lessons. The website is awesome, and I highly recommend it.
While I understand a bot fo what itmeans to be in a key, but I am nbot crystal clear on it, nor I can always tell if a tune is being played n that.... thus level ZERO.

• mary-had-a-little-lamb: mary-had-a-little-lamb on true-piano
  • In key of C
  • In key of F
  • In key of G
• twinkle-twinkle-little-star: twinkle-twinkle-little-star on true-piano
  • In key of C
  • In key of F
  • In key of G
• you-are-my-sunshine: you-are-my-sunshine on true-piano
  • In key of C
  • In key of F
  • In key of G
• yankee-doodle: yankee-doodle on true-piano
  • In key of C
  • In key of F
  • In key of G
• amazing-grace: amazing-grace on true-piano
  • In key of C
  • In key of F
  • In key of G