crissXcross #111
 Dark  CC BY-SA 3.0

Dark pattern with some nice diagonal stitched lines crossing over.

Source Ashton

 More Textures
Snowflake pattern remix #156
 Dark  CC 0

The base gradient edited so now more details are rendered.

Source Lazur URH

Wood@2X #50
 Wood  CC BY-SA 3.0

Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com

Source Atle Mo

Checkered Light Emboss #280
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

Zig Zag #328
 Dark  CC BY-SA 3.0

So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.

Source Dmitriy Prodchenko

Background pattern 7 (grey) #206
 Dark  CC 0

Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net

Source Firkin

Background pattern brown #1945
 Brown  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

"Reptile Skin", Seamless Texture #1119
 Leather  CC BY-SA 3.0

A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.

Source V. Hartikainen

Background pattern 259 (colour 3) #2130
 Colorful  CC 0

Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Background pattern 6 #226
 Noise  CC 0

A pattern derived from part of a fractal rendering in Paint.net.

Source Firkin

Little Pluses@2X #74
 Light  CC BY-SA 3.0

Subtle grunge and many little pluses on top.

Source Atle Mo

Exclusive Paper #23
 Light  CC BY-SA 3.0

Paper pattern with small dust particles and 45-degree strokes.

Source Atle Mo

Dark Blue Gray Wallpaper Texture #901
 Stripes  CC BY-SA 3.0

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