That’s not the usual definition of Protagonist. The Wicked Witch was an antagonist. I suppose you could make more of an argument for Gollum, but I still disagree.
But whatever, i don’t mean to belabor a minor semantic point. If you meant to discuss objects coveted by major characters in films/books/etc, then the Ruby Slippers certainly count.
The Questing Beast, from Arthurian lore.
Captain Flint’s treasure, from Treasure Island.
The Horn of Roland, from Satan Met a Lady (a very bad remake of The Maltese Falcon).
From Andre Norton’s Steel Magic, Excalibur, Huon’s Horn, and a third object whose name escapes me at the moment.
For 10 million years they waited for the answer though.
And you forgot the Roadrunner?
For that matter, Tweety Bird.
And come to that, Pepe Le Pew is still trying to get a fair maiden’s hand - or something.
An infant, and later a package of disposable diapers in Raising Arizona
Marky Mark’s hard on for the middle half of Boogie Nights
Austin Powers’ Mojo
Dragons, in A Song of Ice and Fire series
The Amulet of Yendor, in Nethack
The Bloodsword, in the Bloodsword game book series
The Princess, from Super Mario Brothers