Every Pokemon has been seen in the anime, except for only five Pokemon. However, these five Pokemon are only forms.
However, these Pokemon are Unown !, Unown ?, Burmy Sandy Cloak, Burmy Trash Cloak and Deerling Winter Form.
There are some Pokemon that may not have appeared in any episodes, but in movies only.
It's also interesting to note that the Porygon Evolutionary Line has never had a major appearance in the anime, and probably never will due to the infamous 'Electric Soldier Porygon' episode that put thousands of Japanese children in hospital.
Hope I helped. :)
EDIT: You know, I can't be bothered finding this. You can just use this link to help you. Since basically any Pokemon appears in the anime, you can just click on a type and see how many Pokemon exist of that type (i.e. appear in the anime)