Background pattern 201 (colour) #2497
Grid CC 0A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
More Textures
Climpek #775
Grid CC BY-SA 3.0Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Prismatic Groovy Concentric Background 5 No Black #467
Dark CC 0Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Background pattern 225 (colour 6) #2322
Brown CC 0Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Nami@2X #576
Dark CC BY-SA 3.0Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Concrete Wall 2@2X #80
Wall CC BY-SA 3.0A light gray wall or floor (you decide) of concrete.
Source Atle Mo
"Dark Metal Plate", Web Background #1084
Metal CC BY-SA 3.0A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
Blue Stripes Pattern #969
Stripes CC BY-SA 3.0A textured blue background pattern with vertical stripes.
Source V. Hartikainen
Prismatic Rounded Squares Grid 4 No Background #491
Noise CC 0Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Batthern #324
Grid CC BY-SA 3.0Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
"Polished Stone", Gray Background Pattern #1053
Stone CC BY-SA 3.0A 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
Redox 01@2X #850
Light CC BY-SA 3.0Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Dark Brick Wall #135
Wall CC BY-SA 3.0Black brick wall pattern. Brick your site up!
Source Alex Parker
Flowery pattern 4 #2328
Colorful CC 0Remixed from a vector adapted from a jpg on Pixabay. The tile this is constructed from can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Crisp Paper Ruffles@2X #842
Light CC BY-SA 3.0Sort of reminds me of those old house wallpapers.
Source Tish
Decorative divider 210 #2364
Dark CC 0Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Background pattern 308 (colour 6) #1867
Pink CC 0Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Project Papper #119
Paper CC BY-SA 3.0Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Stylized lion design #2089
Dark CC 0Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
Carbon Fiber Big #326
Carbon CC BY-SA 3.0Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Gun Metal #360
Dark CC BY-SA 3.0With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Prismatic Abstract Geometric Background 5 #401
Noise CC 0Prismatic Abstract Geometric Background 5
Source GDJ
Cross Stripes #47
Dark CC BY-SA 3.0Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Dark Mosaic@2X #122
Dark CC BY-SA 3.0Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Floral pattern 6 #2461
Fabric CC 0A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
Batthern@2X #325
Grid CC BY-SA 3.0Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective