You can attach trim anywhere you want on a garment. One common trim is called ruche. It is like a double ruffle, with the gathering down the center.
Bows are a simple trim item that can be added to a variety of garments. You'll often find very small bows on women't lingerie. They are also suitable for children's clothes.
Appliqué & Patchwork
Appliqué consists of pieces of fabric that are sewn onto a larger piece. In this way, they are similar to a patch pocket. They are a decoration piece and serve no function in the garment.
Patchwork is smaller pieces of fabric in different colors or shapes that are sewn together to create a larger pattern.