If I were to choose one essential oil to support lymphatic drainage, it would be LEMONGRASS. Lemongrass is a truly amazing essential oil in that it not only decongests the lymphatics, but it is antifungal, antibacterial, antiparasitic, anti-inflammatory, regenerates connective tissues and ligaments, dilates blood vesels, and improves circulation. If that is not enough, it aids digestion!
Lemongrass can be used topically, diffused, or taken internally. (I love to take it in capsules.) You can also make “lemongrass tea” by putting 2-3 drops in a cup of hot water. Just be sure to add lemongrass essential oil to the cup rather than boiling it on the stove as the fragile molecules of the essential oil would be damaged with the heat.