Since slide shows are graphical themselves, most people associate them with GUI programs. Yet you can build slide shows just as effectively with some of the simplest and oldest of GNU/Linux tools. A case in point is LaTeX Beamer, which adds extensions to the classic LaTeX typesetting program to produce PDF presentations. Although LaTeX Beamer is capable of considerable complexity, you need to know surprisingly little in order to produce a slide show.
By longstanding tradition, LaTeX is installed by default in major distributions. Beamer is not, although usually it is available as a package. However, until you come to compile your presentation, the documentation for the programs is more important to you than the programs themselves, although you might want to check their availability before you invest your time.