You can find the pattern stamp tool in the tools panel of Photoshop, generally beneath the clone tool. It comes with a number of options to extend it in different areas such as the impressionist feature.
It combines brushes and tiles, you need to have access to both types of presets. As they can be anything, literally an infinite number of combo presets can be created for the tool. It also has the full range of options such as scattering, spacing, size etc but sadly no color dynamics which would have been the most useful of all. You can also apply it as impressionist as well as aligned or not aligned. Select the preset from the control bar. Go to the brush settings panel and tweak the settings such as scattering. The key thing about this tool is that you can use it to fill the screen with imagery but you can also apply localized presets to parts of the image and then change to another and build up a distressed or patchwork etc or just use it to blend in some imagery from another photo.
Fill the document with a solid color or gradient and then select the tool and go to the settings panel and set scattering to the max and set a low count value and instead of seeing some of the design, you will see the brush dabbed scattered version of it with gaps spread throughout the image where the dabs have yet to fill. You can also use this with an alpha channel and then load the selection to use with bevels, effects etc
A small check box but actually quite useful. Tick it ON and then the preset is applied the same as the actual preset, so each application of the tool is applied using the same tile position. You can use the aligned to create more uniform designs.
Turn it off and the alignment depends on the relative position of the start point of the brush stroke so you can create overlapping pattern designs, distressed designs and more. Really depends on what you want but it should not be ignored.
One thing that is lacking, there is no scaling or rotation etc of the pattern so you have the design as initially created. You can get around this by re-sizing the source and then defining it as a new preset so you end up with multiple presets of the same design but just different sizes and angles, not super useful but a workaround.
You can create all kinds of amazing artworks using this feature, please check out the tutorials on that.
You can open any image and define the entire thing as a preset via the edit menu and define command. You can also apply effects such as blur filters or liquefy or halftone etc to the design or perhaps turn the image into a sketch effect by using the other brushes and then defining that as a tile, or using color effects on the image and then defining that. You can use all number of effects on the image and use those as sources for an infinite number of tiles. Go back to the stamp tool and then use those presets and apply the strokes to a new image perhaps filled with black or white et or perhaps blurred image etc. You can then basically use the stamp tool as a filter brush with your image
You can open any image and define that as a preset. You can then go to the filters menu and apply effects such as halftone or oil paint and then again, define that as a preset. You can then apply them to your image to apply localized image effects via a brush stroke so instead having all the image in halftone, you can mix it with blurs as well as oil paint as well as different opacity and blends to create all kinds of unique imagery
In much the same way as above, instead of an image, you can use type. You can use any type. Any color of type. Use any typeface, use any type with effects and perhaps different fills etc and all of them can be defined as a tile via the edit menu. Again, all these source images are added to the presets panel and as soon as you go back to the tool you can select those presets and then apply the type to a new image in 1000s of different ways. You can use different blending modes such as multiply or darken as well as different flows and opacity as well as apply the type strokes to layers and then combine those layers in many different ways and use effects on those and more.
If you have access to the source, and you can always generate the source material. If you go to the presets panel and hover over the icon, you will see details about the name and dimensions and the color mode. Go and create a document with those settings such as 1000 x 1000 and RGB and then drag the design from the panel and it should create the seamless tile (don't shift the layer). Layer menu and flatten and now you can re-color the design using image menu and adjustments as well as add effects to the central part of the image such as blurs and twirls etc. Avoid disturbing the edges of the document otherwise your preset will have a sharp edge in it. You can now go to the edit menu and define it again with the new colors and effects and then use it with the tool.