This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
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
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Sort of reminds me of those old house wallpapers.
Source Tish
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
A seamless background texture of old cardboard.
Source V. Hartikainen
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
A heavy hitter at 400x400px, but lovely still.
Source Breezi