I found myself wanting to install many missing LaTeX packages last night, and it looks like there might approaches to do this in tinytex, but I could not quite work this out.
I ended up writing https://github.com/njtierney/chaletex to help simplify the process of installing LaTeX packages listed in a LaTeX file.
I get the sense that maybe what I'm trying to do is already possible in tinytex, and I was going to ask this as an issue on the repo there, but it seems that @yihui prefers that we ask a question here on RStudio community first, so I am doing that there.
I guess while I'm here, would the workflow suggested in chaletex:
read_tex("path/to/file.tex") %>% tex_extract_preamble() %>% tex_extract_pkgs() %>% tex_install_pkgs()
Be something that could be ported into tinytex?