Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Prismatic Abstract Background Design
Source GDJ
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
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
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Looks like an old rug or a computer chip.
Source Patutin Sergey
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf