It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Green Background Pattern
Source V. Hartikainen
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes