Reddit mentions of The LaTeX Companion (Tools and Techniques for Computer Typesetting)

My top suggestion: documentation of existing libraries.

I think the #1 biggest problem with the libraries out there is that no one has any earthly idea what the hell they are. Zach on Quicklisp has acknowledged this as a big-time failure.

The same situation existed for LaTeX for a long time: there were oodles of libraries available on CTAN, and no one had any idea what to was available, what to use, how they interacted, what was good, what was old, or even how everything worked together. So these libraries languished in obscurity.

Then The LaTeX Companion came out and revolutionized the LaTeX scene. And all this book was was a compendium description of existing libraries.

Lisp badly, desperately, needs a Lisp Companion.

After you've done the net tutorials and you're using LaTeX enough to justify the expense, The LaTeX Companion will make your life easier.

> how does a complete novice that is new to LaTeX know that there is a package that will do exactly what they are trying to do?

Great question. One answer is that there have been books that at least covered much of what an intermediate person would want to know. One is
The LaTeX Companion (wonderful but getting on in years so it misses out on new developments), and More Math into LaTeX (also good, and quite recent, but not as comprehensive as the Companion). Look for these in a university library.

Another answer might be not quite as satisfactory but also has some valididty: if you asked me for an authoritative list of Python packages then I would also say that there isn't really one. LaTeX is big and very, very capable. It changes all the time. A complete list that a beginner person could easily make it through, and which is kept current, is a very big job for someone to do. I don't know of anyone who has.

Find a good book. I have one (I think it's this one: https://www.amazon.com/dp/0201362996/ref=cm_sw_r_taa_ZBGxxbFYM23S2) and the fact it shows you a ton of packages and how to use them fantastic. I haven't come across a tutorial that has remotely as much info as that book.

The LaTeX Companion and/or the Guide to LaTeX are probably the most comprehensive, definitive guides out there. However, for getting started, I'd second/third/whatever the recommendations for The Not So Short Guide to Latex2e (aka lshort.pdf).

I would also suggest that you use XeLaTeX rather than plain-jane LaTeX. It adds nice features like easy support for Unicode and OpenType fonts. You can read up on it in the XeTeX Companion.

Edit: incidentally, when you're writing TeX or LaTeX in plain text, capitalize it thus. ;-)