Dark Wall #817
Dark CC BY-SA 3.0Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
More Textures
Decorative divider 233 #2145
Dark CC 0From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
Crackled Cement Wall #1270
Wall CC 0Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Pattern #1476
Paper CC 0Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
Fabric pattern 2 #2396
Fabric CC 0Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Wallpaper Tile 13 #240
Light CC 0An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Soft Kill #318
Dark CC BY-SA 3.0Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Prismatic Geometric Tessellation Pattern No Background@2X #552
Noise CC 0Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Dark Blue Gray Wallpaper Texture #901
Stripes CC BY-SA 3.0This 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
Tile-able Wall Texture (Light Orange Brown) #1051
Stone CC BY-SA 3.0A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
Prismatic Polka Dots 3 No Background #528
Noise CC 0Prismatic Polka Dots 3 No Background
Source GDJ
Art nouveau tile pattern remix #2529
Green CC 0A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Silver Scales #189
Light CC BY-SA 3.0Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Plywood Web Background #871
Wood CC BY-SA 3.0Plywood Web Background background image for use in web design.
Source V. Hartikainen
Tessellation 10 (variant 2) #2544
Grid CC 0An alternative colour scheme to the original seamless pattern.
Source Firkin
Floral tile 4 #1710
Dark CC 0Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Red & Black Well #1260
Wall CC 0Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Cube Well & Blue #1699
Wall CC 0Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Retro Circles Background 7 No Black@2X #434
Unknow CC 0Retro Circles Background 7 No Black
Source GDJ
Background pattern 227 (colour 2) #2313
Blue CC 0A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 5@2X #466
Dark CC 0Prismatic Groovy Concentric Background 5
Source GDJ
Prismatic Geometric Pattern Variation 2 With Background #471
Noise CC 0Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
Inflicted@2X #118
Grid CC BY-SA 3.0Dark squares with some virus-looking dots in the grid.
Source Hugo Loning