I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
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
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
A version without colours blended together to give a different look.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
From a drawing in 'Hundert Jahre in Wort und Bild', S. Stefan, 1899.
Source Firkin
Colourful background achieved with gradient fills.
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin