do you have an old IBM 5151, 5153, or 5154 monitor with crumbling rubber feet? here's a replacement option for you. š§µ
get a sheet of 3M SJ5009 feet which are pretty close in shape, size, and color. however you will need to modify them a bit.
first, punch or drill a hole for the mounting screw. it's around 3mm.
you'll also need to make a counterbored hole about 3mm down and about 8mm diameter. I found a rotary tool that was just the right size, and I used their routing attachment to control the depth.