To utilize these textures, the user typically goes to the "Patterns" panel in their design software and selects "Import Patterns." Once loaded, the textures can be applied via the Paint Bucket tool (in "Pattern" mode) or through the "Pattern Overlay" option in Layer Styles.

PAT downloads, or perhaps a more on how to create your own?

Adding "noise" or halftone dots to give digital art a traditional, printed feel.

As you are likely looking for a professional way to present or document a collection of for Photoshop or other design software,

A .PAT file is a library format that stores one or multiple "patterns." Unlike a standard JPEG or PNG, which is a static image, a .PAT file is designed for tiling . When applied to a layer or a shape, the software automatically repeats the image horizontally and vertically without visible seams, creating a continuous texture regardless of the canvas size. The Advantages of Using .PAT Over Standard Images

High-quality .PAT textures are engineered to be "seamless." This means the edges of the image match perfectly, avoiding the "grid look" often seen when repeating standard photos.