While the full set of 500+ brushes is a premium product, there are legitimate ways to get high-quality GrutBrushes for free:
The official GrutBrushes website releases a new, professional brush for free every Monday. grutbrushes art brushes 500 free download
The complete collection is a massive digital library used by artists at major studios like . Go to product viewer dialog for this item. While the full set of 500+ brushes is
You can download a free sampler containing 10 diverse brushes and tools to test the responsiveness and texture. grutbrushes art brushes 500 free download
100 Photoshop Splatter Brush Tools by Grutbrushes | Creative Market