If you want to create better content for your presentations you might want to take a look at Visme. It's a tool that allows you to create content such as presentations, infographics, reports, web banners and so on. It has a free section for each type of resource, but they are quite limited. With presentations you have three themes, and the same for infographics. However, standard subscription is $6 a month, which is a reasonable price if you're going to be doing a lot of work like this.