I have made a number of work stands and the most satisfactory design, for me, is made with a base of 16” to 20” wide plow disc, a vertical section of pipe or tube 16” to 20” tall with a hole drilled near the top where I weld a nut/bolt/T-Handle assembly as a locking devise. The top vertical section is made from a pipe or tube which will fit comfortable inside the base tube. The transverse top is made from 1” square tube or round tube 8” or more wide with a couple of end vertical stubs. The easiest way to make those is to cut three walls of the tube and bend the stubs up and reinforce the remaining wall with a weld bead as shown in the image.
The top width depends on how the stand will be used. Stability results from keeping most of the mass concentrated toward the floor and keeping the transverse top width to a minimum so the work is centered over the vertical shaft reducing the moment arm.
Most were made in the early days and almost all the components were easily attainable scrap. Each band saw has two, each drill press has one, the forge has two so that makes eight. When I was cutting a lot of longer structural steel to build equipment for the shop I made a couple of stands with 2” rollers, scrap from a food processing line. They were OK for that specific purpose but I no longer use any. The rolling feature is now mostly annoying.