Search LaTeX documentation with Alfred
(1) Ready Alfred to accept a terminal command. Per this support document, the standard method is to type &gt; and then the terminal command. Similarly, in LaunchBar the action is built into the basic index, too, and one can initiate it with term or similar.

(2) Type texdoc PackageName where PackageName is the LaTeX package you're looking for the documentation for. For example: texdoc enumitem or texdoc thmtools.

It'll open the documentation PDF. That's it!

Note that of course you can also do this from the command line directly if you open a terminal window.