Searched my collection of Slopes and found at least one more version (but these parts are so rare we dont need them on the PT):
-3 slopes with round pin, medium holes and extra wide curved lip (would go across the stud but has normal hole to the inner slope)
-1 slope with small holes and bottom ridges from the newer versions (I guess it is a mismould, also the logo is upside down compared to all other ones)
apart from that, its hard to define a "standard" version because they have been used for a long time...
f was the first standard, then c and then b. d and e are exots (i have 200+ 3660 and of these only 7*d and 8*e. the rest are equal amounts of b, c and f.). Then I would say make f the new a version.
-3 slopes with round pin, medium holes and extra wide curved lip (would go across the stud but has normal hole to the inner slope)
-1 slope with small holes and bottom ridges from the newer versions (I guess it is a mismould, also the logo is upside down compared to all other ones)
apart from that, its hard to define a "standard" version because they have been used for a long time...
f was the first standard, then c and then b. d and e are exots (i have 200+ 3660 and of these only 7*d and 8*e. the rest are equal amounts of b, c and f.). Then I would say make f the new a version.