This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Prismatic Groovy Concentric Background 2
Source GDJ
A repeating background of thick textured paper. Actually, it turned out to look like something between a paper and fabric.
Source V. Hartikainen
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
Prismatic Snowflakes Pattern No Background
Source GDJ
Sort of reminds me of those old house wallpapers.
Source Tish
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
The image is a seamless pattern of a fishnet.
Source Yamachem
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
This one is amazing, truly original. Go use it!
Source Viahorizon
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
White handmade paper pattern with small bumps.
Source Marquis