Lineman Pliers. Along with the other stuff, but it seems like no matter what the project, I always grab the lineman pliers. Grabbing a screwdriver for electrical work, grab lineman pliers too. Rigging something with zip ties, lineman pliers to pull it tight and cut the excess. Forgot a hammer? Smash with the pliers. Cotter pin falls out? Grab a length of copper and twist.