A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed 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
Might not be super subtle, but quite original in its form.
Source Alex Smith
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ