Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A seamless pattern formed from a square tile based on a jpg on Pixabay. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
One week and it's Easter already. Thought I would revisit the decorated egg contest at inkscape community: http://forum.inkscapecommunity.com/index.php?topic=118.0
Source Lazur URH
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
Prismatic Chevrons Pattern 5 With Background
Source GDJ
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees