Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
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
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Seamless Prismatic Geometric Pattern With Background
Source GDJ
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Prismatic Groovy Concentric Background 3
Source GDJ
A pale olive green background with a seamless texture.
Source V. Hartikainen
The base gradient edited so now more details are rendered.
Source Lazur URH
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
A new one called white wall, not by me this time.
Source Yuji Honzawa
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
8 by 8 pixels, and just what the title says.
Source pixilated
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen