I have two 'classes' of Wonders I'd like to see added.
First, some of the really early Wonders from the beginning of the game or a Neolithic Start option, like the Tarxian Temple complex on Malta, or the White Temple in Uruk, Si an Bruh (Newgrange) tomb in Ireland, Gobekla Tepe in Anatolia, the Maumbury Rings in England, Carnac Stones all over northern France and Britain, the Goseck Circle in Germany (a wooden version of a henge calendar complex over 2000 years older than Stonehenge!)
Second, some of the great 'Missed Opportunity' Wonders:
Great Dam of Mar'ib - an irrigation and water control ediface built in the 18th century BCE - what Civ VI's "Great Bath" Wonder should have been.
Dionysius' Workshop - Started in Syracuse, Sicily, 410 BCE, the world's first Military Research establishment, where the crossbow, the catapult, and the Quinquereme warship were all invented within 10 years!
Cholula Pyramid - 300 BCE to 800 CE, in Mexico, by volume the largest pyramid ever built anywhere. Cheops was a cheapskate by comparison.
Baths of Caracalla - in Rome, 212 CE: a Classical culture/health-related wonder?
Temple of Kulkulcan - It's what the game keeps calling "Chichen Itza", which was the city, not the *&#$%^ Temple: Get It Right For Once!
Su Song's Water Clock (Hun Yi)- 1094 CE, a monumental mechanical engineering marvel, another scientific wonder, which we have far too few of in the game.
Grand Bazaar (Buyuk Carsi) - 1455 CE, in Istanbul, a wonder commemorating Trade and Merchandising, which may be truely unique among Wonders
Les Invalides - built in Paris 1670 - 76 CE, a Home for disabled military veterans run by the state, but later one of the largest military museums in the world: take your pick of possible themes for this Wonder.
Smithsonian Institution - 1855 CE: a Museum that includes Archeology, Natural History, Industrial History, Aeronautical History, Portrait and other paintings, and Ethnology all in one set of buildings
Pasteur Institute - Founded 1887 CE and still going strong as one of the world leades in biomedical research against infectious disease. If the game ever does include a Plague mechanic, this has to be included with it.
Disneyland - 1955 CE, the world's first Theme Park and still attracts more tourists than any other theme park in the world except Disneyworld in Florida: this should be the capstone to a Tourism Victory, not Rock Bands.