The cardboard tubes from paper towel rolls make good cord covers. We also got a length of plastic tubing from the hardware store, cheap black stuff, and made cord covers from that as well. We got 1-inch wide stuff, so plugs didn't fit through, but we just cut a slit the length of the tube, put the cord in it, and the plastic is rigid enough so it closed right back up on its own. The cardboard tubes you may have to replace from time to time, as they are nibble-able, but it keeps the cord within safe!
For wood that you do not want nibbled, you can just wrap the bottoms of the legs of furniture in foil and tape it in place. It's not the prettiest solution, but it is effective. We actually had to do that with the corner of one wall in our old (1890) house, as our bunny suddenly decided one day that 100+ year old plaster was tasty. Yuck!