How many Pokemon have only one type? In other words, for how many Pokemon is Type2 blank?

467 Pokemon

Explanation:

There are 890 Pokemon, this number is counting the new generation, I mean 8 generation, in this case, we have 467 Pokemon only with one type.

There are not any website with this data, I had to create an Excel sheet, then I add different lists, I found the 890 different Pokemon with the first type and the second, the last step was to make a filter, with the type 2, where only show me Pokemon with the type 2 = blank.