Floral pattern 7 (colour 6) #2286
 Brown  CC 0

Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.

Source Firkin

 More Textures
Triangular Psychosis 4 #236
 Noise  CC 0

A colorful triangular background, variation 4.

Source GDJ

Retro Squares Background 5 #395
 Dark  CC 0

Retro Squares Background 5

Source GDJ

Carbon Fiber Big@2X #327
 Carbon  CC BY-SA 3.0

Bigger is better, right? So here you have some large carbon fiber.

Source Factorio.us Collective

Brushed Alum Dark@2X #66
 Dark  CC BY-SA 3.0

Because I love dark patterns, here is Brushed Alum in a dark coating.

Source Tim Ward

Floral Seamless Pattern Background #261
 Fabric  CC 0

PDP

Source GDJ

Seamless Cardboard Texture #1212
 Cardboard  CC BY-SA 3.0

A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.

Source V. Hartikainen

Pattern generator #161
 Noise  CC 0

A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.

Source Lazur URH

Abstract Tiled Background Extended 9 #520
 Dark  CC 0

Abstract Tiled Background Extended 9

Source GDJ

Batik Parang Rusak Seamless Pattern(faqeeh)-remix #2450
 Dark  CC 0

As the original image 's page size is too large for its image size, I remixed it.

Source Yamachem

Fabric pattern 2 (colour 4) #2393
 Fabric  CC 0

Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin