Here are some resources I have found helpful if you are looking for 100% free digital brush sets. I may write another blog post about this topic, showcasing the brush sets that are worth paying for as well. Just let me know down in the comment section if you’re interested.
This is the largest free brush site I have come across in my search on the internet, and I use it quite often. Basically, if you can think of it, it’s on here. They’ve got trees, clouds, patterns, speckles, animals, grass, hair, grunge, texture, etc. There is even a sister site to this one called ‘Vectoreezy’ if you are looking to get clean vector images for your Illustrator designs. Now all of these are uploaded by regular artists, just like you and me, and they tend to have a disclaimer whether they would like to receive credit for their work or not. So read the description about the brush set thoroughly before you download.
They have compiled their very own wonderful list of brush sets that are awesome. So, they’ve already done most of the work for you! What I really like about their list is the pencil, realistic charcoal, and marker brush sets. When painting digitally sometimes it’s hard to replicate that ‘traditional’ style you get with good old fashion pen and paper.
My Photoshop Brushes
This is another great resource. There are a lot of famous, professional digital artists that upload their personal brush tool sets on here with reference photos to what they painted themselves using those particular brushes. So, if you want to paint like Connor Burke, a renowned concept artist, his brushes are literally on this website. And they’re free!
DeviantArt is not only a website dedicated to artists all over the world uploading their work for critique, and selling prints. There are a lot of artists that upload their own brushes for free as well. Again, you will have to look at the description to see if it is available for personal, or commercial use. Just type in brushes, or brush sets in the search bar, and see what you’ve got! Because it is an open source site, not all of these brushes will be high quality, so use your own discretion.