Well, I drive a 3/4 ton a lot and what I use varies.
Sometimes a jag of green oak firewood.
Sometimes an ATV.
But my favorite is about 30 ft of 3/4 chain. It will weigh in at over 200 Lbs.
Plus a good conversation piece.

I have heard of folks bolting a steel plate under the bed for weight also.

Don

1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!