These rubber feet look like a good replacement for NeXTstation pads that may be turning to goo. They're about the same size as the originals except the thickness is 3/16" instead of the original 1/16". They have 3M adhesive tape too.
https://www.ebay.com/itm/334749984607 (
https://www.ebay.com/itm/334749984607)