I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A bit strange this one, but nice at the same time.
Source Diogo Silva
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Tiny little fibers making a soft and sweet look.
Source Badhon Ebrahim
Zero CC tileable Laminate wood texture, photographed and made by me. CC0
Source Sojan Janso
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
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
Prismatic Abstract Geometric Background 4
Source GDJ
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
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
There are many carbon patterns, but this one is tiny.
Source Designova
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin