A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin