[eesummers]

besides what has been said before (first aid kit, gloves, emergency blanket, etc),
a nice combo swiss army knife, here in the desert, something (hemostats) to pull the spines from the teddybear cactus that seem drawn to the boots.
I always carry a couple tea bags, some caffeine and electrolyte packets to add to water just in case.
binoculars which can double as a signaling device.
sun screen, bug spray, life straw.