A black tile-able background with paper-like texture.
Source V. Hartikainen
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Prismatic Abstract Line Art Pattern Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless paper background texture colored in pale yellow. This seamless texture is ideal for those who need a yellow background image for their website. The texture resembles paper.
Source V. Hartikainen
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Seamless Prismatic Quadrilateral Line Art Pattern No Background
Source GDJ
Black And White Floral Pattern Background from PDP.
Source GDJ
White circles connecting on a light gray background.
Source Mark Collins
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Sort of reminds me of those old house wallpapers.
Source Tish
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
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
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Used a cherry by doctormo to make this seamless pattern
Source Firkin
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida