For a cruiser you really only need a few taps. What ever you do make sure if your buying one type it's a plug style. Otherwise you will need a taper, plug, and bottoming taps. Also remember if your getting a tap for the temp senders or anything that plug into the coolant area you want a pipe tap.
Most common taps. Get these and you should be covered on the main stuff. There are smaller ones. But most of us aren't going to need them.
Buy some thread cutting oil! Your crap will last longer and won't break. Also get the right drill size for the tap.
Tap size---Thread count
6mm----1
8mm----1.25
10mm---1.25
10mm---1.5
12mm---1.25
12mm---1.75
So that's 6 taps and 6 drill bits. Stick with good stuff and you will be happy for a long time. Good place to buy single taps.
https://www.travers.com/Default.asp Page 138. Remember you want plug hand taps. And you don't really need dies as most of our cruisers are bolted together. You can always go buy a new stud or bolt.