You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Black And White Floral Pattern Background from PDP.
Source GDJ
A floral background formed from numerous clones of flower 117.
Source Firkin
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Prismatic Geometric Pattern Background 2
Source GDJ
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
An alternative colour scheme for the original seamless texture formed from an image on Pixabay.
Source Firkin
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß