Essential Oils You'll Want to Put in the Bath. Essential oils have amazing health and wellness benefits, They are also great for relaxation and natural beauty and skin products. This list of 20 of the best essential oils to add to your bath is great! It includes tons of simple oils for beginners, and you can make your own essential oil blends to add to your bath. For aromatherapy, healthy skin, and even improved mood, you'll want these ideas for essential oils to add to your bathtub.