Cordage is one thing that muse have countless uses and you should always carry it with you because it is very difficult and time consuming to make in a survival situation. The cordage should be multi-ply so it can be broken down into smaller fibers if needed. There are a few forms of cordage. One main go to is the seven strand para cord, the only disadvantage is the inner strand are hard to work with. The second is Tarred bank line, it has 3 ply and is easy to work with. The third is Mule tape, it was designed to pull wire through conduit and is very strong, The type I try to carry has wire laced in it that can be used for trapping in a survival situation.