I would include Sasori but majority of his puppets look the same but i think Sai is the most artistic visually that we've seen
Also honorable mention goes to Konan
Sasori - mainly because of his human puppets, even though it's twisted and Frankenstein like; it bangs!
Sai - drawing talent is OP and the fact that he can draw things with intricate details then bring them to life in a matter of seconds is also worth mentioning.
when Sai, Konan, or Sasori can make a gigantic, weaponized version of themselves down to the last detail, then and only then will they be in Deidara's league.