PowToon has a great selection of available fonts. The difficulty is in choosing the right one. Check out the video to see the fonts and for some quick tips on choosing. The main thing to remember is to keep in mind what impression the font will give the viewer. If your video is for your business, think carefully whether or not your customers/clients will get the right perception about your business.
People may not say it was the font that turned them off from doing business with you because it's kind of a subconscious thing. Your business or your video just won't "feel" right. It's a gut instinct kind of thing.
The same can be said about your PowToon video in general but let's save that for another day.