Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
A version without colours blended together to give a different look.
Source Firkin
Prismatic Curved Diamond Pattern No Background
Source GDJ
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
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
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Plywood Web Background background image for use in web design.
Source V. Hartikainen
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin