Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
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
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
A free web background image with a seamless concrete-like texture and an Indian-red color.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin