I was wondering because:
EXAMPLE Tentacool,Frillish ... Tentacruel,Jellicent
They're close dopple-gangers in the two generations so I was wondering,is there a dopple-ganger for every pokemon?
(you don't need to talk about legendaries)
example: Milotic, palpitoad,etc
No, there aren't dopple - gangers for each pokemon.
Like Pikachu, Gardevoir, Golem Etc.
Hope this helps!