I started reading the grammar for Novegradian. It looks extremely promising as a reference point for what I plan with my current project, so I'll definitely keep on with it, even if it is a bit... lengthy. I don't have much to comment about it specifically yet; I think I'm still in the introduction.
One thing I'm trying to figure out is how much (invented) history I want to present in the grammar that I write. I do have a basic historical trajectory sketched, but I kind of want to present this language as an isolate, even if I do have an explanation for where it came from. Although, if I commit to an in-universe perspective, I suppose that means I'd have to mark some fraction of the language as a reconstruction, as it's supposed to be an exinct language.
I suppose I should do the thing that I now realize is obvious, and look up resources on languages that went extinct in the past few centuries.
Okay, a few skims of Wikipedia later, and I've got a promising cross-section of languages to investigate.
All right, I can't think of anything else to say here, so I'll wind down.