My motorcycle kit has:
2 packs of quick-clot
3' of surgical tubing (powdered, in a Ziploc, so it doesn't stick to itself)
1 small roll of gauze
1 roll of tape
3 chemical light sticks
1 large plastic trash bag
1 single-edge razor blade
1 mylar "space blanket"
I also carry a flashlight all the time, so it's technically not part of the kit.
The contents of the kit were decided on after extensive thought about the situations I might encounter. Spurting blood - quick clot, then the tourniquet if it comes down to that. Gauze to cover an eye socket or for "feel-good" over cuts. Trash bag and tape to cover a sucking chest wound or exposed intestines. Razor blade to cut away clothing and cut tape or plastic.
Space blanket to help deal with shock, cold weather, coverage from rain, and visibility to find the injured person again.
Light sticks - one for the injured person, two to mark the crash site so I and/or an ambulance can find it.
For a motorcycle crash, my thought is that other than stanching spurting blood, or a sucking chest wound, there's not a whole lot I can do. So the plan is to deal with that to keep them alive, then (worst case, I'm the only person available) I mark the site and ride off for help. Cold, dark, and rain are also likely factors.
Dressings and gauze aren't very useful; any wounds are probably going to be dirty to start with, and the EMTs will cut them off as soon as they arrive. The only reason I have the small roll of gauze is that people tend to pick at things that are hanging out that shouldn't be; covering them can prevent additional damage.
With the incidence of contagious diseases being so high nowadays, you'd better hope someone else shows up who knows CPR, because I ain't gonna. I'll do the obsolete style that depended entirely on chest compressions if I need to.
The last time I was at a crash there was no phone service, so I had to stop motorists and send them off for help. I wound up staying with the guy who wrecked. (he lost a leg to a road sign) Send three or four people, preferably in different directions. If there are no people around, you'll have to do the best you can and then go off for help on your own.
Snakebite isn't something you normally have to worry about on a motorcycle, but if you're in the woods it would be important to have a snakebite kit. If you're going to be out for days you'll probably want tools to remove splinters or objects left in puncture wounds, and maybe a needle and thread to sew up gaping wounds.