Thoughts:
Brilliant Professor David Salo, who translated The Lord of the Rings languages for the movies, has done this once. It's posted on his Constructed Languages facebook group, somewhere between 2005 and 2015.
You could also try Zompist Bboard website by Mark Rosenfelder. One of the major facebook conlang groups is by Jonathan Fleury, Linguistics and Conlangs. I was a top admin there 5 years ago, but have not been on much since then. But there are two or so other major facebook groups, though you will not see me on them.
Janko's list of numbers in a great many languages acts something like this for conlangs, as evidenced by a conversation by great conlang veterans Elemtilas and Khemesis on either my recent Klingon thread or my recent Ferengi thread, both Star Trek conlang and pseudo-conlang groupings.
I have made surveys over the past 15 years of all conlangs readily available online, as well as of all "ritual languages" and "language games" found by me as I went through a lot of ethnography (anthropology writings). However, I am a scholar of conlanging and a conlanger, both in general, and in particular with regards to conlangs in famous books, tv, and movies. I also give some special attention to historic conlangs. For a summary of some of my insights, see my recent post about the history of conlanging to Zompist Bboard. Notably, I have discovered that conlanging is not some unique and clever modern Western thing, but very similar to "ritual languages" and "language games" attested from peoples around the world in ethnography but sparsely attested in the otherwise sparse written record (from all time). And I have a good sense of what ever has been written because I specialize more in combing ancient texts than in combing ethnography. Some 15 years now, plus a BA Linguistics.
"Ritual languages" are not exclusively for rituals but usually languages used for ritual and myths by shamans (priests) and bards (story teller specialists).
It is true that none of them are of the sophistication and modern scientific insight of modern online conlangs. Then again, they often contain archaic words from hundreds of years previous, which is a feat modern online conlangs cannot match. They're often derived or parallel to the major language spoken by the people of which is the "ritual language".
I was almost a petroleum engineer, I could have made a lot of money. But I had very good reasons to get the BA Linguistics instead. And society should reward me for it. And recently has but not sufficiently. Alas, now they all must pay for their contempt of science as increasing numbers of people in the USA suffocate to death, entirely preventably, of the coronavirus in spite of immense sums of money being spent to expedite the vaccine (without much regard for safety?). Look not to me, I have done more than my part and played the Archimedes and the Diogenes before Alexander the Great. Yet I am revered, celebrated, and frequently begifted in my native country. Who has recently announced, I have not checked it, free vaccines for all by October from Mother Russia. ( I know who it is and thank you, Tree to the Foxes. )
Anyway, um, there's also the Linguifex and FrathWiki wiki's that list a lot of conlangs.
There's lots of work to be done in trying to dig up and make more accessible online conlangs which are not on the internet. And similar things, pseudo-conlangs and possible conlangs. I know of no one who has done more toward this end than myself, and I have not done much toward this end.
You know, the world population is now far higher than it was even in 1700 AD, yet there are very few dedicated scholars, with degrees in linguistics or any ability and mindset comparable. Though probably in the next 100 years we will lose 3/4 to pandemics and nukes, sadly. And one must consider in such research the good that could be done by spending that time on, say, Native American languages, or any of the hundreds of major ancient language texts that we'd all benefit from having of which a good gloss and glossary.
Notwithstanding, I myself think conlanging and its associated exploration and puzzling over of language science and other topics of science and scholarship, is the wave of the future, and in coming centuries to swell in popularity, if not for the 3/4 thing. And so over the past 15 whole years, I have dedicated quite a bit of time to conlanging and deciphering, studying, and expanding conlangs from famous books, tv, and movies. But I have not everywhere been celebrated in this, not among language scientists, not among conlangers. But everyone has things that they regret of themselves or their predecessors.
I don't know if we will ever build on or take up your project here. There is much to do and I have done a lot already. Perhaps there will be a year or two in the future yet for this. I am quite able to do it, I can read all academic literature in linguistics quite well, if I look up various terms and puzzle over them. I have been doing that for 15 years. But I do not specialize in that exactly, my specialty is logographic writing systems, which is a lot certain things about phonology plus anthropology plus art history / iconography. Yet I have painstakingly studied many reference grammars of the highest quality, and have some sense of work on languages from every era and corner of the globe.
I recently met someone from maybe France who did their Masters on conlanging, at Zompist Bboard. But I cannot find his name now. He replied to one of my recent posts, perhaps the Okrand Atlantean one. We did not talk at much length. He did not seem especially accomplished or enthusiastic for the topic. It sounds like a good Masters topic if you're on your way out of academia. I was told to do such things on the side. So I just flipped sides. And subsequent studies have shown I chose well: Many people often does make a babel. I always hope they prove me wrong but usually people disappoint me quite a bit.
But my very difficult work documenting and deciphering conlangs and pseudo-conlangs from books, tv, and movies has not been met with much kindness and warm reception. I have even encountered certain jealous and narrow-minded fellows who have purposely discouraged me, directing sorrow, making remorse: facing the books and jingling felicity.
So I am a pioneer scientist of great accomplishment, a visionary. So I am like Jean-Francois Champollion and Rosine Champollion, Egyptologist, or ... Nikolai Aleksandrovich Nevsky and Iso (Isoko) Mantani-Nevsky, Tangutologist. A cold welcome for science, a warm welcome for the plague and The Mask of The Red Death.
I'm happy to hear of it. But I'd encourage you to work with me and others because I know a lot and know what I'm doing. I know a secret or two, too. But I'm more accessible on facebook. Just join this facebook group and ask around:
History of Conlangs, Conlang Decipherment, Asemic Writing
https://www.facebook.com/groups/1559372287639844/
...
Here is an image for this essay. I make them for the facebook post versions of my essays and sometimes share them here to show my raison d'etre, my je ne sais quoi, my flare for art. Recall, I am also a sort of art history major and was celebrated for my art in my youth.
Image: Janko Gorenc, The Prize of Slovenia, King of Languages. He's a major name in conlanging because his list of numbers from a great many languages and conlangs has recorded the names of many conlangs from over the years. Slovenia is otherwise notable for dedicated and charming scholars, like Hungary. Slovenia is more well-rounded, though, like Italy, and notable for good skiing and hiking. It's like Albania but different. For languages, Slovenian is easier because it's Slavic whereas Albanian and Hungarian are more interesting. Where I am from, there are a lot of Hungarians and Albanians. We do not see a lot of Slovenians.