I've got a regular sized board (with the Flintstones cover) and an mini board. The mini board has that coated fabric cover, my Flintstones cover seems to be just plain old cotton.
The padding looks a lot like polyester quilt batting.
I just had a thought - my cover isn't too worn, but it is dirty. I could throw my cover in the washing machine! Thanks for getting me to do that!
The padding's a thin foam layer.
HGTV has some tips on ironing boards and ironing HERE . They say "Starch your ironing board cover so it will stay cleaner longer." and "A silver ironing-board cover is best for heat disbursement, but if you don't have one, simply place a layer of foil under the cover to reflect the heat."