I have 2 that have been my favourites both by fisher price one was called from memory Royal Potty was like a thrown and had rewards for child when they used it. Other one I am using now for my son it is also fisher price looks like a real miniure toilet even has pretend toilet roll holder it also rewards with music.
They have prob been my favourite cost me about $ 60 aus each
However after the novelty wore of my kids favourites have always been a little set steps with a seat that goes on the big toilet lol #

my daughter seemed to really like the potty seat that goes on top of the regular toilet and it is definetly less mess cuz you just attach it to the toilet seat... good luck

My baby girl had one that my mom bought in europe .. it was a very simple one shaped like a duck and had a nice pink color and the cool thing was that it played music each time she would use it .... so that was her fave one.. she also had one that looked like a miniature toilet and one that looked like an arm chair one that looked like a princess chair but after all the the cool things in the expensive ones she like the simplest one ...