Now that you mentioned it, I never really noticed it before, but I have a couple of bags of the Band-It stainless ties that I know are UL listed, but they only say it on the instruction sheet that comes inside the bags. Nothing at all on the ties themselves. You’d think that if they went to all the trouble of getting them listed that they would slather it all over them. I guess if anyone ever calls me on it I will have to dig one of the bags out of the trash.
I also have a bag of those nylon standoffs that you put a screw in the middle and run the tie through the slots. Nothing marked on those either, so I guess you have to check that any accessories like that used with plenum rated ties are also rated.