Mellotron

I feel like that's like saying there is no Rhodes or Wurlitzer (which certainly have distinct sounds). I don't really know much about a mellotron, but with a quick look-up, I'd probably just use Keyboard Synthesizer or something.

A mellotron is apparently a kind of analogic sampler, reading a magnetic tape under each key of its keyboard. So it can basically make any sound, and have any range or transposition. I guess it doesn't make sense to add it to the list then.