We've posted about making your own fabric softening sheets, but if you want a pre-made alternative you might be interested in this 6 pack Etsy offering from lollipopguild:
...each pillow is a mix of fresh herbs and flax which will leave your fabric refreshed without toxins. Each pillow can be used for about a month and then can be use as a sachet all over the home and car. Your cloths will come out smelling of lavender. *As pointed out by a reader, these are currently sold out, but we still wanted to post them as a "green good idea", hopefully inspiring some of your to make your own. And perhaps with enough interest lollipopguild will offer a few more in the near future.