Well, of course, you come here, and you go to nSpir3d.com (associated with Renderosity).

E-On Software is still in business, but owned by Bentley. (https://www.bentley.com/en/about-us/news/2015/september/14/bentley-enlivens-reality-modeling-through-acquisition-of-eon-software).

Vue itself seems to have moved out of the hobbiest realm and into the professional realm. So, it appears that the majority of the people purchasing current copies probably are model-builders themselves, or are able to purchase pro models freely. So, there are only a few places where you can purchase content for anything earlier than Vue 2016.

The managers of this site are trying to encourage the old Vue model-builders and plant makers to re-publish their content here. Maybe more items on nSpir3d.com And this fellow is giving a try - http://www.vue3dmodels.com/ The claim in this store is for "tons" of models, but I counted only around 34 items. But, it could be I didn't spend enough time on that site to really discover everything.

CGTrader has a bunch of very interesting items that are full terrain scenes made by a fellow known as "Raffyraffy." And they have a lot of individual items of good quality.

And, I saw a bunch of the old Arabian desert items on DAZ or some place like that. Models that had been built by the old Cornucopia3D in-house contractors.

I would put up more of my inventory of some 500 models here, but there seem only to be about 35 Vue'ers who come to this site. Not enough to justify the labor of getting everything updated and making the necessary set of product renders. So, I've been kind of discouraged. But I will put things up for the older versions of Vue here from time to time.