Ooh, there's lots of things that I haven't done.
I haven't:
Played a Mummy or Vampire
Tried the Military, Law Enforcement or Education careers.
Completed the 'Private Aquarium' or 'Possession is 1/10th of the Law' LTWs
Played the Bunch family
Managed to get a Sim to Immortal (I promise as soon as I do I will have a story!)
Explored the tombs in China or France
Had a Visa level of 3
Played on Short or Epic lifespan
That's all I can think of now.