Excellent lists there! There is a lot of fertile ground for Firaxis there, so to speak.
I'd like to put in a word for Lake Baikal that you have in your list. I've been campaigning for its inclusion for years.
I'd like to see it in Civ VI and to raise awareness of this amazing lake. It needs to be preserved for future generations.
Great information on it here:
Lake Baikal Information and Facts
Lake Baikal is nothing short than a natural wonder. It is the deepest, oldest and largest freshwater lake by volume, containing one fifth of the world’s fresh water.
The 25-million old lake has a maximum depth of 1,642 meters and is a living museum, boasting approximately 1,700 animal and plant species, out of which two thirds are endemic. It is one of the clearest lakes in the world, the biggest lake in Asia and 7th biggest lake in the world by surface area. Its 23,615 cubic kilometers of fresh water surpasses the volume of all American Great Lakes combined.
The "Galápagos of Russia"
The lake is also called the "Galápagos of Russia", due to its uniqueness, which is also attested to by the fact that more than 80% of its animal species are endemic (only live here). The Baikal seal (or the nerpa) is the only true freshwater seal, and one of only three populations of freshwater seals. The other two populations are comprised of subspecies of the ringed seal.
Among the many plant species, one must note the marsh thistle, which is at the eastern limit of its geographic range at Lake Baikal. The lake’s climatic asymmetry also led to a great variety of plants in its basin: pine forests dominate the eastern part, deciduous forests the northern part, and coniferous forests and mountain steppes the western part. The forests surrounding the lake host 10 endangered plant species.
A World Treasure
Undoubtedly, Lake Baikal is one of the world’s greatest treasures, and it should be treated as such. The surrounding landscape with its mountains, tundra, boreal forests, steppes, islands is exceptionally beautiful. The unique wildlife is an unimaginable asset, along with the 1,200 historical, cultural and archaeological monuments in the region. However, the threats surrounding Lake Baikal are real, and its unique properties could be lost. Various steps are currently taken in order to make sure that the area remains protected.
https://www.lakepedia.com/lake/baikal.html