Obviously, DIES! Since you are loading pistols, get CARBIDE dies. Don't waste your time on anything less. I did and regret it. Applying case lube, removing case lube, crap sticking to the cases and scratching the plain dies - stupid. Get carbide dies!
Then get a Lee Factory Crimp Die (FCD), which is a carbide taper crimp die that you use LAST. It does a wonderful job of final-sizing the cartridges, greatly eliminating chambering problems.
And a set of the LNL bushings for each die in the set, so you can do the quick changes the press is designed for.
You will also need a tumbler. I like the vibratory cleaners, but some like the rotating drum (rock hound) tumblers. That means media.
You will need a scale to set the powder thrower on the LNL. Maybe some pharmacist's weights, if you want to be really thorough.
Manuals. ALWAYS use at least two different sources for powders and charge weights. These can be supplemented by downloads from web.
Calibers. You need to be able to measure cartridge length, bullet OD, etc. Most people cope with dial calipers; digital is easier to read and has the added bonus of inch/metric conversion, if you shoot those wussy Euro calibers.
Primer tray. You need to get ALL the primers facing the same way to load them into the tube.
That should keep you busy - and broke - for a while.