The push blocks that I use in the shop are not fancy, but they afford me excellent control and are cheap to make. I make half a dozen at a time and leave them around the shop at different machines. Besides being used as safety accessories, they also get abused as mallets, cauls, anvils, blocks, and more.
I start with a section of construction grade 2×4 about 8″ long. Using the bandsaw, I make a rip cut 1/2″ to 1″ from one edge (depending on the thickness of stock it will be used for), stopping about 1-1/2″ before I’m through. Then I make a second cut to complete the notch. I cut a curve on the backside of the block to make it more comfortable to use and give it a quick sanding to remove any splinters. That’s it.
The block works equally well to apply downward, or downward and forward pressure. When making narrow rips at the table saw, I keep the push block on top of the workpiece and tight against the fence, and pass it right through the blade.
When one gets cut up too much, I just toss it in the scrap wood box.