These jersey dresses from Old Navy are amazing! Okay actually, I can't speak to quality yet because I haven't had them that long yet and haven't run them through many washes yet. But they are super stretchy and soft, and I've been enjoying throwing them on quickly when I want to be comfortable. I have the solid maroon version too, which I included in the Fall Outfits for Busy Moms post (HERE) for that exact reason--comfortable and cute! I'm a huge fan, and they're currently available in 6 colors or prints. I'm normally size 6/8 or S/M and got these in M. It's currently on sale for 35% off online only, making it $19!
If you don't have a stretchy dress in your closet, you need to at least explore them! I'm not saying dresses are for everyone. Some people don't like wearing them no matter how comfortable they are. But, everyone should at least TRY a stretchy dress! I feel like you're missing out otherwise. ;P Some of them might be shapeless or a swing style like the one I'm wearing, which might not work well with some body shapes. However, there are others that have more seams and shape that are still super stretchy and soft. (See a recent roundup of them HERE.)
Lastly, my exact cardigan finally came back in stock! But sizes are already going quickly. It's oversized and I wear it in S...could have even maybe gone for XS. See it HERE.