The varieties they grow:

https://todolicitrusfundacio.org/en/the-citrus-collection/varietal-groups/

This list includes varieties of Citrons, Mandarins, Pummelos, Lemons, Limes, Bitter Oranges, Sweet Oranges, Grapefruits, Kumquats, Papayas, Australian Limes and citrus related varieties, including some hybrids.

I'm doing the poor man's version of that, with a single tree. Rootstock is Sicilian lemon, one of the branches is grafted rangpur, and I'm trying to graft mandarines and oranges into it. I'm also thinking about grabbing one of the kumquat's branches just for shits and giggles, and grafting there too.

I do want finger lemons and Buddha's hand, like in the article. Soon® I'll get those.

Buddha's hand is fairly well known.