You will likely see posts and info about "neck sizing dies", and while I have bought a neck sizing die a time or two over the years, I have never seen where there was any advantage to the extra cost.
Not saying there might not be a time, just that I have never seen the time when a properly adjusted Full Length sizing die didn't do just as well.
Also you will read posts where people praise the Lee products in general and the Factory Crimp Die specifically.
Well, while I do use a limited number of Lee products, the Factory Crimp Die is simply taking money from your pocket and placing it in Lee's most of the time.
And yes I have bought some of those dies.
However, in most cases, a properly adjusted two die set for bottle neck cartridges and a three die set for strieght wall cases like handguns or 45/70 will do everything that is needed.
Not 100% of the time, but the big majority of the time.
Yes, if you load cast boolits in a bottle neck cartridge, you'll need some way to flair your case mouth.
And in some cases and with some chambers with handguns something like a taper crimp die may be needed if the roll crimp is not properly done or the chamber is overly tight.
But this is rarely the case. Have never seen it, and yes I do have a taper crimp die for my .44. It sits is it's nice green box, has been tried, then returned to the box. Never paid for itself in results, not even close.
So, all that to say this, before your fill up you bench with extra and likely un-needed extra/special dies along with making a big hole in your wallet, make sure there is a need beyond properly adjusting your 2 or 3 die set.
Crusty Deary Ol'Coot