Crayola has a trademark on the smell of its crayons
The odour is described in the Canadian trademarks registry as:
Crayon Scent Mark. Canadian Trademarks Database 1986544. Crayola (2019). A unique scent of a pungent, aldehydic fragrance combined with the faint scent of a hydrocarbon wax and an earthy clay.
In Canada, a trademark can be anything that is used by by a seller to distinguish their goods or services from those of others, including "a word, a personal name, a design, a letter, a numeral, a colour, a figurative element, a three-dimensional shape, a hologram, a moving image, a mode of packaging goods, a sound, a scent, a taste, a texture and the positioning of a sign."Trademarks Act. RSC 1985, c T-13. Canada (2021).
Unfortunately, I have not been able to find records of anyone litigating over a scent trademark.