A golf towel is great for
A golf towel is great for keeping the hands clean and will clip on your belt or belt loop so it is always handy but out of the way. And I can't believe no one mentioned duck tape. How can you go anywhere and do anything without duck tape! ha! Zip lock bags. A small container to dump out packs of hooks, sinkers, etc if you need to "search" for things. A hat with lights built into the bill makes a great tool at night without using the hands. Small file to sharpen those dull hooks. Stainless Steel pliers with extra long nose is a great tool for most any task around the water. And many use circle hooks to make it less likely the fish will swallow the hook.