There are many TeX packages available which provide functionality in areas not covered previously in this guide. A great resource for discovering new and interesting packages is CTAN's list of packages by keyword, linked below.
There are several interesting packages related to music available for TeX. A few are collected below, and be sure to look at the package documentation for instructions on their use. For a more comprehensive list, see the CTAN music page.
There doesn't seem to be a large body of resources available for TeX with engineers in mind, but a list of certain resources which may be useful is presented below.