There is an in-print translation. I believe Wiktenaeuer also has at least a partial translation (it may be full, not sure) but reading that much on computer would be maddening for me at least. He tends to be pretty...longwinded as well.
https://www.amazon.com/Academy-Sword-Gerard-Thibault/dp/1904658849
Definitely get the print version rather than Kindle, trying to cross reference plates and text would be maddening as he has big plates that he repeatedly references (similar to Meyer).
He is not as "be the lion" as Meyer. An overly broad take would be that he thinks that as long as you've got better geometry than your opponent you'll be fine, and the whole game is incrementally improving your position (with punishment if your opponent tries something weird).
That said, be warned that he uses an odd grip that rules out some hilt styles, and also there aren't a lot of people practicing his art.
There's a full translation of Thibault available for purchase: https://www.amazon.com/-/Gerard-Thibault/dp/1904658849/
Sadly from the comments it seems the newest edition is smaller than it used to be,and even the old one wasn't as big as the original book, which might be important at times with the detailed and dense pictures.
For primary sources:
Two books are completely translated for True Destreza: Viedma and Thibault
There are also partial translations, for Pacheco, Ettenhardt and a few others I can't remember off the top of my head.
There is also MANUEL ANTONIO DE BREA for smallsword, which is post-rapier Destreza. I think he is more or less fully translated.
For secondary sources:
There is some content on youtube.
Alberto Bomprezzi's Channel It's some sort of mixed Destreza.
Associació Catalana d'Esgrima Antiga (Barcelona) I am unsure what Author(s) they use.
Tim Riveras Spanish Swordsociety. There is some information on Viedma there.
Puck Curtis lectures on J Diamond's channel. It's Pacheco.
Puck Curtis own channel It's Pacheco and lots of videos of his kids.
Phil Swift's Channel I think it's on Pacheco.
Ton Puey's Academia Espada The rapier is Rada. Think the two swords and Montante is mostly Godinho.
UmeHFS(my club) has a series on Rada. It is still in its infancy.
UmeHFS also has some workshop videos with Aleix Basullas Vendrell aka /u/Azekh. It's Rada.
Also, check the gilded comments on this sub. There is a book worth of comments there by /u/Azekh
Currently I believe the only full English translation is Greer's: https://www.amazon.com/Academy-Sword-Gerard-Thibault-dAnvers/dp/1904658849
If you can read French I think there is a full transcription there: http://www.escrimeurs-libres.fr/travaux-du-celn/
There was a subreddit at one point, but currently inactive: https://old.reddit.com/r/ThibaultRapier/
You also have a facebook group: https://www.facebook.com/groups/185583465301323 (not hugely active, but you can still look through the archives)
And another one which you might want to join, with weekly meetings to read the whole thing through: https://www.facebook.com/groups/326097029120322
I've got a few articles over at https://blog.subcaelo.net/ensis/tag/thibault/
Then there is Matthew Howden's website: https://www.historiccombat.com/gerard-thibault/
One of the most notable distinctions between Thibault and the LVD mainline is his way of gripping the rapier. He also has a slightly different foot position in the default stance (toes of the front foot pointing slightly inwards). He might be a bit more willing to use curved lines and voltes than others? He is also not using the Spanish terminology, or even its direct translation. Perhaps our Destreza specialists can tell you more, /u/Wertilq, /u/tim_stl, /u/Azekh?