One that I can think of off the top of my head is the Lucid Dream No. 14. It was one of the earlier toys that my partner and I bought (before we really knew about material concerns and all of that). And it is pretty much perfect when it comes to size, shape, and curve for hitting both her g-spot and my p-spot. Plus it's waterproof. Brilliant, except that it's a jelly toy and it would be sooo much better if it were silicone.
So what do you have that you would want to improve just slightly to make it the "perfect" toy?