There was one had --HEAT RETAINING--on the label but I did not need it then and can't recall correct name. I'm sure a clerk would know.
There was a thread around a while ago - something about it had been taken off the market because of a fire hazard but that it had been redone and was now being sold again. You could try to google microwave potato baker lining or something like that - or perhaps a cutie will come along with better help.
Are you talking about the warm and natural batting? I buy this at JoAnn's, but have not done it for the microwave use. I have started using a batting that is bamboo for some of the projects that I have done. I like the way that it feels, but don't know how it will wash up. Good luck finding what you want.