I was teaching Storyline recently and one of my students wanted to put a check mark image into his project. Before I could blink, he was on Google, had searched for a check mark image, found a ton of them, downloaded the one he liked, and added it to his project. Done and done!
Of course, the image was copyrighted (as are most images you'll find via Google searches). Given that he is a Storyline 360 subscriber, I showed him a better way to icon-glory that's not only cost-free but copyright-free and royalty-free.
From the Storyline 360 ribbon, select the Insert tab. From the Content Library section, click Icons.
In the Search Icons area, he typed check mark and pressed [enter]. The result was more check marks than he could possibly ever use. Better still, he was able to quickly change the color of the shape once it was loaded onto his slide (something he would have been unable to do with a checkmark image lifted from the Internet).
Similarly, you can use the Search feature to find anything from puppies to kittens to boats. And again, everything you find is free to use and/or modify in your Storyline project.