Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
The image depicts an edo-era pattern called "same-komon" or "鮫小紋"which looks like a shark skin.The "same" in Japanese means shark in English.
Source Yamachem
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
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
Formed by distorting an image on Pixabay that was uploaded by gustavorezende. To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
To get the repeating unit, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
White little knobs, coming in at 10x10px. Sweet!
Source Amos