You may use it as is, or modify it as you like.
Source V. Hartikainen
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Tiny little flowers growing on your screen. Nice, huh?
Source Themes Tube
Prismatic Abstract Geometric Background 4
Source GDJ
A version without colours blended together to give a different look.
Source Firkin