Good list of stuff, we were talking about tools to bring, not spare parts.
But since you brought up spare parts, I carry 3 fiberfix spokes, these spokes allow replacement without taking off the cassette, and they're lighter in weight and fit in a very small tube-shaped container.
You shouldn't need spare bolts for racks and fenders if you go over all the bolts before that day's ride; Brake pads are a given, as are a couple of spare tubes, some even take a folding spare tire, usually a lighter weight tire till they can find a better replacement but some carry the same tires they use, guess that would depend on where you're going; a single spare valve core, I see no need for a spare derailleur unless you're going off-road, but if you're going to that you can put on a crash guard instead, they're cheap and easy to put on, on a road trip the panniers will protect the derailleur; duct tape you don't need a lot of, just 3 feet at the most, a couple of different lengths of zip ties, because zip ties do have a habit of breaking; extra bungee netting or cording if and depending on what you use; chain lube; and spare chain links, cables? I haven't broken a cable in a very very long time, probably for at least 45 years, I don't worry about carrying a spare cable, even if a brake cable breaks I still have another brake, I can get to a bike shop and have it replaced. I'm surprised a spare rotor wasn't mentioned, not that I would carry one, but some might, especially if offroad; but on a road bike if a rotor goes bad, I still have the other brake.
Spare chain isn't necessary, if you break a chain and don't have spare links you can refasten the chain minus the broken link or links, all that will do is make it so you can't use the first one or two gears and last one or two gears, all the other gears you can use, then simply find a bike shop, you're going to want to get a new chain even if you do have links, so you're going to a bike shop regardless.
All of this should be checked before you go, why run on a rotor or pads that's half worn out? Replace it before you go, or start a trip on a half or even just a quarter worn out chain? be safe and replace it before you go. Same with cables, if the cables haven't been replaced in a while just replace them so their new at the start of the trip. Eliminate things that can go wrong before you go, then once underway do a pre trip inspection before the start of every ride, checking for stuff, making sure bolts are tight, the chain has been wiped down and new lube applied if needed, etc. A pre trip should only take 10 minutes at tops, most people do post trips and not pre trips, I do post trips because I'll arrive at a campsite before 2 in the afternoon, I have the time after I set up camp, but the morning I just want to pack and go and leave as early as I can and not fool around with checking stuff.