This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
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
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
The image depicts a seamless pattern of the design which includes a stylized lotus and a stylized crane.I referred to the original image in a book which is into public domain.
Source Yamachem