Yesterday, I was wrestling a large bag of dog food into the storage bin. You know the kind of closure that you have to rip the thread out of it to open? I was about to toss the red thread that held the bag shut, when I thought........ hmm... this might look good on a card! I've also used the ribbon that manufacturers put in the shoulder seams of sweaters and such so that they won't slip off a hanger. Usually, they are dyed to match the clothing item. They are good to use for cards as well. Security envelopes make great die cuts. I've made lovely layered flowers with these.
We waste so much on a daily basis, that it feels good to make use of some of what would end up in a landfill. It definitely changes the way you look at things!