I carry;
1) the harley tool pack that came with the bike
2) a few hefty garbage bags
3) hand-crank flash light
4) zip tie's, roll of electrical tape
5) a quart of oil, and an extra hose and clamp for my oil cooler
So far, the hefty garbage bag is the only thing I've needed to use...
I used it as a temporary rain coat during an Oregon coast, summertime downpour. The weather was so nice when I left home that I left my leathers at home. Big mistake!!!
6) I now keep my leathers in the side bags too