It may seem too obvious, but rope would be hugely useful in creating defenses for wherever you decide to set up shop. Zombies tend to be pretty stupid, and if you're dealing with the shuffling zombies of Romero or The Walking Dead, you can make tripwire with a long rope and definitely buy yourself a whole lot of time when the walkers come a-knockin'. In the event of a zombie bite on one of your or your teammate's extremities, you could also use rope to tie off the wound if you're going to try to amputate to stop the zombification from taking hold. It has been known to work, mostly because the zombie infection doesn't actually take a hold on a person's body until it reaches the brain. If you remove the contaminated part of the body before the infection has a chance to travel, you can prevent the zombification. Hershel from The Walking Dead TV series is a perfect example, as he has a leg amputated shortly after a bite and manages to live to fight another day.