I think you are asking for more information than you realize.
You should go down to a library and check out a couple of books on the history of HD, or better yet there are a number of coffee table type volumes that you can buy reasonably that tell you most of the historical data , and a catalogue from you rlocal dealer will identify the model designations , at least for the current models.
Your question would take hours to answer even on a basic level.
Frames engines, front ends , brakes, sheetmetal electric or kick ...there are a thousand variations on the theme. And the historical deal is very intricate...for example, there are at least five different versions of the panhead...which years were "outside oilers?"
There are too many questions buried or hidden in your inqury...you need to do some basic research thru printed matter then ask more pointed a question.
Your question is similar to asking what different options have been offered for corvettes over the years, how many engines have been offered?
It ain't a simple discussion. For example do you want to know what the designations mean this year or do you want to cover JD, VL, UL, EL , FL, FX, XL, XLCH, FX, (the letters just keep on churning)
manny