The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Prismatic Hexagonalist Pattern No Background
Source GDJ
Dark blue concrete wall with some small dust spots.
Source Atle Mo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
White circles connecting on a light gray background.
Source Mark Collins
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
Prismatic Groovy Concentric Background 2
Source GDJ
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
There are many carbon patterns, but this one is tiny.
Source Designova
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Looks like an old wall. I guess that’s it then?
Source Viahorizon
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Embossed lines and squares with subtle highlights.
Source Alex Parker