“Unique” is an interesting adjective to try and rank. I’m not sure what has the “most unique” worldbuilding.

For example, Avatar the Last Airbender has a really interesting and well fleshed out world, but ultimately it draws heavily from our own world as well as from eastern (and western) folklore and history, so I’m not sure it could be called unique.

The video game Kenshi comes to mind as having a really alien-feeling setting. One which sits somewhere in between post apocalyptic, eastern fantasy, and alternate history, while being none of the above. Perhaps that’s a “unique” setting?

Star Wars is pretty good.

The Expanse.

The Dark Crystal. Fraggle Rock if you’re looking for a little more levity.

Lord of the rings comes to mind.