Yes, you can find icons made from third-party designers, and then add them to your project having WPF framework. For example, from this answer you can use already built icons from Microsoft if you're having a purchased version of Visual Studio. Read more
here...[
^]. If you read this answer, then there are three other links that you can use to search for packages for icons. Of which, you might consider going to this URL:
https://www.iconfinder.com/[
^].
Now, coming for a third-party package, this
Modern UI Icons[
^] package is a great package that you can use. You can download the .zip file to add this to your project. Hopefully this would be enough for your use too. :)