Cartridge Set Up Essentials

Endless. Suggest you watch one or two of the great videos Michael Fremer has on this, free on YouTube. 

As for me, having tried a few and studied a lot more, the only ones truly "essential" are the stylus tracking force gauge and whatever overhang/alignment jig you prefer. These can be downloaded and printed out for free. But if free rubs you the wrong way then the one I recommend is the Mobile Fidelity Geo-Disk. This has the advantage of being the same thickness as a record. You could of course simply lay the paper printout on top of an LP, same difference.

A lot of guys will freak, but you can get just as good results with $20 worth of the Shure stylus force gauge and a sheet of paper. This is coming from a guy with a Koetsu mounted on a Conqueror on a roughly $20k front end. Images like nobody's business. Done it both ways, love the Geo-Disk for its simplicity. 

As for eye strain, any dime store magnifying glass will take care of that. Not that its needed. Believe me, that last little fraction of a millimeter, that's not where its at. So probably most essential of all is a sense of proportion.

Along with the MINT, I bought a recommended magnifying glass.....much easier and more accurate.

The Dr. Feickert protractor, while really expensive, is the best I have used.  
A digital stylus gauge that measures to 1/100 of a gram makes it easy to dial it in.  
I have a Geo Disk and it works fine, but not as good as the Feickert.  I have not tried the MINT but as I recall you need one of theirs for each tonearm you use.  I have two tonearms and might add a third so the Feickert being universal is a better deal for me.  
I'd like to try a Fozgometer to dial in azmiuth, but I doubt I'll buy one anytime soon.  

dodgealum, the DB System's protractor is the most accurate because it magnifies the error. It is also relatively inexpensive. You need a small pocket mirror to set the azimuth (steal one from your wife), a stylus brush,
a digital stylus gauge, A small bright light, a Hi Fi News Test Record and whatever small tools you need to tweak your tonearm, little screw drivers, allens, etc. The digital gauge is a bit more expensive but the manufacturers will now give you a recommended VTF down to 10ths of a gram because they know this VTF will settle the cantilever into the right position for optimal symmetry of the coils in the magnetic field and put the stylus at the right rake angle. While there are counterbalance scales that can get down to 10th's accurately I have never seen one that accurate for VTF setting and they would probably cost more than a digital gauge.
The test record is absolutely mandatory. You can not set the anti skate correctly without one. The scales on the tonearms are only estimations.
Even with my old eyes I do not need magnification to set azimuth with a mirror. Just a bright light should do it. You place the mirror on the platter then the stylus on the mirror (defeat your anti skate!) You adjust your azimuth until you get a perfectly symmetrical hour glass shape in the mirror. This method doubles the error and makes it easy to see when you are right on. Leveling the cartridge body is the wrong way to do this. You only care about the stylus and they are frequently not perfectly perpendicular to the body.

Good Luck and yell if you need help,
Mike