And marigolds! They are the best. They bloom until the first frost. Let the seed heads dry on a paper towel and then put them in an envelope or small paper bag shut with a clothespin and you are ready to plant in the spring. Just tear the flower head apart to separate the seeds. I have been fortunate enough in the past that if I leave the whole plant in the garden until spring or just before, some of the seed heads not eaten by birds will self sow. This year I didn't have as many but I still had marigolds coming up by themselves around the garden.
Another tip for plant markers is one I read about in a garden magazine or somewhere years ago. Use plastic knives (from take-out) or buy a box. White or any color you like and use a permanent marker to write the name of the flower, herb, or vegetable you are planting.