Although candies come in all shapes and sizes, there are roughly five different categories of size.  Not all candies or chocolates come in all sizes.

Changemaker -- These are bite size candy bars, typically packaged
in bags.
Regular -- These are the standard size candy and chocolate bars,
typcially packaged in 24, 36, or 48 count boxes.
King -- These are larger candy and chocolate bars, typically
packaged in 24 count boxes.
Bulk -- Not a size as such, many candies, such as gumballs, come in
10, 20, 25, or 30-pound quantities.

Candy Sizes