Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
It’s big, it’s gradient—and it’s square.
Source Brankic1979
Pattern formed from simple shapes. Black version.
Source Firkin
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
CC0 and seamless wellington boot pattern.
Source SliverKnight
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Black And White Floral Pattern Background Inverse
Source GDJ
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo