Have you checked out Deviant Art recently? If not it is worth your time to get reaquainted.
Deviant Art is a site set up to showcase digital artists best work. I have a page there myself showcasing some of my favorite work from my YouTube channel. But Deviant Art isn't just a great place to look at great artwork it is also a fantastic source for creative tools as well. Many of the artists on Deviant Art upload resources for programs like Adobe Photoshop making it one of the best sources for Photoshop Brushes and Textures. I have used this resource several times in my YouTube video projects.
To find brush sets on Deviant Art just do a search for psbrushes, or to save you time here is the link https://www.deviantart.com/resources/applications/psbrushes/popular-all-time/. This will bring up a page showcasing the most popular Photoshop Brushes on Deviant Art. Deviant Art can be a bit glitchy at times, if you land on a page and get an OOPS! missing page notice just try back again later.
If you are unfamiliar with the process of installing custom brush sets into Adobe Photoshop here is a video showing the process. Photoshop Brushes: How to Find, Download, and Install Custom Brushes