From an image on opengameart.org shared by rubberduck.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Neat little photography icon pattern.
Source Hossam Elbialy
Prismatic Geometric Pattern Background No Black
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso