From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
The image depicts a shell seamless pattern.I used an OCAL clipart called "Shell" uploaded by "jgm104".Thanks.
Source Yamachem
Number five from the same submitter, makes my job easy.
Source Dima Shiper
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry