I have half of:
That golden piraka combo of Thok, Vezok, and Reidak?
And Likhan + Kikinalo
And both Toa Hagah, fully built, minus Iruini's chest piece.
And I believe half of the first Takanuva's vehicle. I'm honestly not sure what happened to the other halves of most of the models, and I'm missing all of their masks except the golden Thok head and Likhan's. As for pieces, my rarest would probably be a silver Miru Nuva.