Inspired by If a corpse is polymorphed into a creature, does it retain personality?
True Polymorph can turn a creature into an object
Creature into Object. If you turn a creature into an object, it transforms along with whatever it is wearing and carrying into that form. The creature's statistics become those of the object, and the creature has no memory of time spent in this form, after the spell ends and it returns to its normal form.
Since a corpse is an object, a creature can be True Polymorphed into a corpse.
Can it then be raised, by a spell such as revivify or true resurrection?