A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Prismatic Abstract Line Art Pattern Background
Source GDJ
From an image on opengameart.org shared by rubberduck.
Source Firkin
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Subtle scratches on a light gray background.
Source Andrey Ovcharov
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A floral background formed from numerous clones of flower 117.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
A bit of scratched up grayness. Always good.
Source Dmitry
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Zero CC tileable pine bark texture, photographed and made by me. CC0
Source Sojan Janso
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo