If time allows, students should be taught how to coordinate music patterns to animation patterns. Music links can be found here. Sound effects are available on the Internet and some in Power Point. Used sparingly and with careful selection of quality, they add a tremendous depth of feeling to a presentation. Due to the inclusion of inappropriate sounds in all sound web sites I've seen, I do not have a link of sound effects for students to browse through as I do for music.
Students can also use a microphone to create their own sound effects.
Again, teachers should decide in advance how much time to allocate to this activity. Due to the need for complete silence, the recording session usually has to be the same period for everybody in the class. The students take turns using the microphones. Video also adds fascination to a presentation. Video clips can be downloaded or student created video can be added.