Baggies of Veggie and Herb Garden Seeds
There are many methods of preserving seeds. The value of plastic baggies is obviously that they keep moisture out, however I've been warned that it's best to also allow seeds to breath and to not be trapped within a container where they could sweat moisture and cause mold. I've mixed results using different methods. It's even possible to mix seeds with grains of rice or other very absorbent materials to keep seeds dry. If you didn't mind some rice growing in the mix, why not. I've had fun growing rice and eating the grass. In terms of becoming more post-plastic, mason jars are good for storage if you're okay with the seeds not breathing much, or if you can keep them dry, small paper baggies work great and you can also write labels right on the paper.