Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
From an image on opengameart.org shared by rubberduck.
Source Firkin
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
A new one called white wall, not by me this time.
Source Yuji Honzawa
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
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
Gold Triangular Seamless Pattern No Background
Source GDJ
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
A seamless background of warped stripes on paper.
Source V. Hartikainen
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Prismatic Hexagonalism Pattern No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen