This is a simple plug to cover the holes on the Harbor Freight 69054 Workbench. It should also fit the 93454 bench. I'm not sure but I think they are really the same bench.
I made these because so much dirt falls down into the drawers of the bench through the holes in the top of the bench. I used this bench for 3d printing and for mounting a atlas metal lathe on them so it doesn't matter that these plugs stick up a little.
These shouldn't be hard to print. I printed them at 80% fill from ABS. I would think PLA would be just fine too. You will need 12 of these to fill all the holes on a Harbor Freight workbench. On my Da Vinci 1.0 printer I printed all 12 at the same time in about 45 minutes. Nice and quick part to print.