Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
It’s big, it’s gradient—and it’s square.
Source Brankic1979
This was formed by distorting an image of a background on Pixabay.
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
The image is a design of blue glass.How about using it as background image?
Source Yamachem
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
A simple bump filter made upon request at irc #inkscape at freenode. Made a screen capture of the making here: https://youtu.be/TGAWYKVLxQw
Source Lazur URH
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
A seamless background tile of aged paper with shabby look.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin