A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
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
A white version of the very popular linen pattern.
Source Ant Ekşiler
An alternative colour scheme to the original seamless pattern.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Prismatic Basic Pattern 2 No Background
Source GDJ
Alternative colour scheme to the original.
Source Firkin
A bit strange this one, but nice at the same time.
Source Diogo Silva
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
A seamless background texture of old cardboard.
Source V. Hartikainen
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 pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
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
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett