This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
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
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A pattern derived from repeating unit cells each derived from part of a mosaic in paint.net. The starting point for the mosaic was a picture of some prawns!
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Looks like an old rug or a computer chip.
Source Patutin Sergey
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin