We reuse regular canning jars as well as "disposable glass jars from almost anything with a resealable lid.
Spice jars are great for refilling with bulk spices from the HFS or with ones we dry from our garden. We have even used dried spices from our garden as part of gifts at Christmas.
I have reused jars when I lacto-ferment veggies (mostly sauerkraut and kimchi) and make ketchup since you don't need the seal like you do when you are heat canning veggies.
I also reuse jars to store leftovers and as cannisters. I have dry beans, pop corn, rice, nuts, etc. all in glass jars on my counter ('cause I like the way they look all lined up there
) and in my cabinet.
The lady we get dairy from delivers milk, yoghurt, and goat cheese in reused jars.
We reuse glass juice bottles for water bottles.
We reuse beer bottles and make great home brew!
I save youghurt and other smallish plastic containers for starting plants in the spring.
We also reuse egg cartons for eggs.
Old t-shirts make great family cloth
I also re-purpose our own and thrift store clothing for fabric for diaper covers (sweaters for soakers and knits for the decorative fabric of wraps) and baby clothes, and I have started making a collection of t-shirt bags for Christmas gifts. I have some lacy curtains from my SIL's house that are just waiting to become play clothes for my nieces.
Kitty litter buckets are great! That's what we use for a diaper pail. We also store and carry tools in them and have one for rock salt that sat close to the door without looking too tacky during the winter when we had snow. I like the buckets that have a removable label so you can have a plain white bucket.
We compost. I also save the tops of carrots and bits from celery and onion peels for a few days in the fridge when I am going to make stock.
I save buttons from clothing that is gong on to other uses. They can be used to replace ones if one goes missing, but they also make great play items for sorting for kids old enough not to eat them
and great craft items.
That's all I can think of off the top of my head.