I save and shred all my mail including envelopes, inserts, junk mail, flyers, delivery menus left on my door, unwanted catalogues, etc. Some of it ended up in the compost but the last time I moved I saved bags and bags and BAGS (yes that much) of it for months before I moved and used it to pack my boxes. It took quite a lot of the shredded paper to compact and cushion the nooks and crannies in the packed boxes of my items but it was really effective and I had plenty to go around. You'd be surprised how much that accumulates, even if you get most of your bills electronically! I used it mainly when packing my kitchen items, including glassware, plates and collectibles and didnt have any issues. This not only saved me tons of money because all the packing material was free but was a good way to reuse what already would have been discarded. After I unpacked I simply recycled the shredded material which I would have done anyway. The slim padded envelopes that Amazon sends smaller-ish items in are also great for packing/storing glassware and other fragile items.
I love all these other ideas though, so great to read all these examples of conscious consumption! <3