From OHOM, the Jun Self-Heating Diffuser: "Add a fresh, inviting scent to any room with this handcrafted ceramic diffuser set that only needs a little water and a few drops of oil to create an aromatic sanctuary. The diffuser holds 5 oz. and comes with a special charger that uses induction energy to heat up the metallic layering on the bottom of the diffuser. And as an added bonus, the warming base doubles as a wireless phone or earbud charger." Shown in Moonmist Blue, $98 at Nordstrom, where you'll also find it in 6 other colors.

From Vörda, a wood diffuser (as low tech as you can get: it has a small cavity on the top where you drop the oil) in Japanese Cypress: "A simple yet elegant design inspired by "vās", the Latin word for a vessel that is often used for carrying flowers. Handcrafted from the wood of the Japanese hinoki cypress tree. Native to Japan in East Asia, the hinoki cypress has been long cherished for its subtle and crisp scent of fresh lemon, and ornamental qualities. The delicate pale yellow of the wood adds a touch of light to your décor." In two sizes, Small for $39 and Large for $48; oils sold separately, the Hinoki cypress oil is $24 for 100 ml but  you can mix and match woods and oils. At Vörda.