IMHO, there is a difference in Theming(tells a story) and decor(fits atmosphere).
Rarer themes;
Great America's original Yukon territory had lumberjacks log rolling and log climbing and a woodshop along with great landscaping.
Disneyland's main street is a little more common and copied, but few have the Disneyland energy of horses, trolleys, omnibus etc.
Bon Bon land's excrement candy theming is strangely great.
Pandora(great, could be awesome)
Rookburg and Klughiem in Phantasialand.
Disneysea's Arabian Coast and Mediterranean harbor.
Port Adventura's Polynesia
Peppa pig is not rare as a theme park, but Peppa Pig World as a themed area in Paulton's park is themed perfectly.
And my favorite rare... Mysterious Island Disneysea
Bucket list; Haw Par Villa theme park and Disneyland Shanghai Treasure Cove
Dream theme; while not a themed area, put together this would be awesome; Aulani resort Hawaii, Disneyland's Trader Sams/Tiki Room/Tropical Hideaway/Jungle cruse and WDW's Polynesian resort.