Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
Abstract Tiled Background Extended 8
Source GDJ
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective