SoundBible is a great website if you’re looking for free or royalty-free sound clips to add to your presentation. It has over a thousand free sound clips and sound effects that can be used in PowerPoint presentations.It is quite simple to use as well – just type in the sound effect you’re looking for (i.e. birds chirping), select the sound you like, and click the sound icon to download the clip in a format of your choice (.wav, .mp3 or .zip files)