If "pallet" refers to a platform for moving goods:
* Forklift (the machine used to move pallets)
* Conveyor belt (a system for moving goods)
* Cart (a smaller platform for moving goods)
* Hand truck (a device for moving heavy objects)
If "pallet" refers to a bed:
* Couch
* Mattress (on its own, not part of a bed frame)
* Bunk bed (a bed that has multiple levels)
* Hammock (a swinging bed)
If "pallet" refers to the color:
* Bright
* Vivid
* Light
* Deep (depending on the specific shade of "pallet")
To provide the best antonym, please give me the context in which you are using the word "pallet."