I personally carry a standard set of allen keys to tighten or adjust my handlebars, footpegs, primary cover and gas tank. I carry a 1/2 inch spanner and adjustable spanner for clutch cable adjustments, gas tank, and mirror adjustments. A set of torx bits also are good to have for the Primary Derby cover incase I need to change or add primary fluid on the road. And a small flat head and phillips head screw driver for the brake caliper, hose clamps and battery terminals. Battery terminals are notorious for rattling loose on Sporty's. And multitool like the one Gerber or Leatherman. I have one of each but prefer the Gerber. The Grber multitools are easier to grip because they have sooth rounded handles rather than the open, blunt edges of the compartments where the extra gadgets live in the handle that you need to squeeze which dig into the fleshy parts of your hand.
I keep a handful or zipties on hand as well as they come in handy on every long ride I have ever taken even if its not for the bike. I ride a Harley Sportster with spoke wheels and changing a tube on the side of the road isn't really an option.
I don't carry sparkplugs as I have not had a sparkplug issue in the 74,000 I have ridden on my bike. Some people still have sparkplug fouling, but it seems rare with all the people I know riding bikes with fuel injection. But I do carry extra exhaust manifold nuts as mine have a tendency to rattle off from time to time because again the vibration from the Sporty engine is a bit much.
I've had clutch cable snap on me while riding and carrying one just isn't worth it. I wouldn't want to be on the side of th road replacing that on my bike. Not difficult and the only tool I didn't mention that is needed on a Sporty is a snap ring plier, but that isn't even necessary if you're just looking to get home. On a Sporty, Clutch cables and throttle cables should last a long, long time with proper maintenance. Mine get lubed twice a year. I would suspect that most manufacturers use pretty sturdy cables in this day and age as those are parts that see a lot of stress, but I could be wrong as only have the Sporty and a Suzuki Savage. And the Savage hasn't really been tested by me or my lady too much that we would even have to worry about breaking down more than 50 miles from home.