Extracting Sims 4/EA Patterns

The way objects and clothing work in The Sims 4 means that every single item has its own unique texture. There is no generic collection of patterns that get applied to items. It doesn't work like The Sims 3 did.
If you want to extract the texture of an object the best way to do it would be to clone the item that you want the designs of using S4Studio and then export them from the program.
So if you want the pattern from th City Living curtains, open Studio and select the option to create a Standalone Recolour. Locate the item on the next screen that shows up and then click Next. You can filter by game pack and use search terms across the top of the screen.
Once you have saved the package you will be taken to a screen with a 3D preview on the left and object information on the right. All of the colour options should show up as coloured sqaures at the top on the right. Clicking on each one will change the preview and you will be able to see the texture on the right side of the screen on the lower half. It is called the Diffuse Texture. Here you can use the Export button to save the texture file somewhere on your computer where you can open it with image editing software to be able to edit it.