A comeback for you: the popular Escheresque, now in black.
Source Patten
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
A version without colours blended together to give a different look.
Source Firkin
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Prismatic Curved Diamond Pattern No Background
Source GDJ
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Prismatic Groovy Concentric Background 3
Source GDJ
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Tiny circle waves, almost like the ocean.
Source Sagive
Prismatic Abstract Geometric Background 3
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
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
This light blue background pattern is quite pleasing to the eye, it consists of a tiny rough grid pattern, which is seamless by design. That's it, if you like the color, you can use this seamless pattern in a web design without making any further modifications to it.
Source V. Hartikainen
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Found on the ground in french cafe in kunming, Yunnan, china
Source Rejon
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen