No handkerchief.
I do carry a terry cloth rag dangling from my back pocket to wipe sweat, or blood, or wipe hands. Don't blow my nose on it though. If I blow my nose on something, it's a paper product that gets promptly tossed in the trash.
I go through a lot of those in summer, as I'm prone to sweat.
Never without a pocket knife. Never without a handgun or AR within at least easy reach. Got plenty of lights at hand too.
One thing I've added as an essential now is a phone. I keep records on it for client hours, photographs, get notifications from surveillance cameras, has a built in flashlight, compass, and even...a phone to call someone in an emergency.
Cash, ID, and quarters.
