Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Prismatic Abstract Line Art Pattern Background
Source GDJ
Background formed from the original with an emboss effect
Source GDJ
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
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
Sharp pixel pattern, just like the good old days.
Source Paridhi
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Alternative colour scheme. 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 pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Psychedelic Geometric Background No Black
Source GDJ
A white version of the very popular linen pattern.
Source Ant Ekşiler
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
You may use it as is, or modify it as you like.
Source V. Hartikainen
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A green background pattern with warped vertical stripes and a grunge look.
Source V. Hartikainen
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim