Black And White Floral Pattern Background Inverse #196
 Dark  CC 0

Black And White Floral Pattern Background Inverse

Source GDJ

 More Textures
Starring #585
 Dark  CC BY-SA 3.0

If you need stars, this is the one to get.

Source Agus Riyadi

"Dark Brick Wall", Background Pattern #1024
 Stone  CC BY-SA 3.0

Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.

Source V. Hartikainen

Seamless tile 4 #1812
 Red  CC 0

Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern

Source Firkin

Background pattern 8 (black) #209
 Dark  CC 0

Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net

Source Firkin

Prismatic Rounded Squares Grid 3 No Background #489
 Noise  CC 0

Prismatic Rounded Squares Grid 3 No Background

Source GDJ

Abstract Arbitrary Geometric Background #497
 Noise  CC 0

Abstract Arbitrary Geometric Background derived from an image on Pixabay.

Source GDJ

Background pattern 272 #2057
 Brown  CC 0

A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Background pattern 232 #2297
 Dark  CC 0

Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.

Source Firkin

Triangular Psychosis 3 #235
 Noise  CC 0

A colorful triangular background, variation 3.

Source GDJ