I actually have no idea
wood
This depends on the type of water used to make ice.
Well, first thought would be keep in in the freezer. Covering the ice cube with an insulating material would help, sawdust or woodchips is what they used to use many year ago.
Squares
punett square
A square
petroleum jelly, stick inside the cube
Beach scarves make good towels, but check the material first to make sure it can handle the water.
Copper used to be very common, now many kinds of plastics are used. PEX is one of the most popular.
Velour material is material used to make tracksuits etc.
The same as the container that's used to hold the water while it freezes ! An ice-cube can be as small as 1 inch square - or hundreds of feet !
a fiberglass insulation blanket that has a plastic jacket, they sell them specifically for hot water tanks