If you usually work with Keynote for presentations, it is possible that you have tired of the themes that Apple's program brings by default and that you do not want to pay for new ones, so right now your best chance is to get hold of a few free themes.
The "Goodies: Keynote Themes 1" pack is a pack of ten themes that will give a little new air to your Keynote, which surely comes in handy given that some of the default themes are already well known.
And the best of all is that it goes as usual, at zero cost. They are something more than 100 megabytes that are worth it.
Download | Keynote Themes