Smooth Wall@2X #28
 Light  CC BY-SA 3.0

Some rectangles, a bit of dust and grunge, plus a hint of concrete.

Source Atle Mo

 More Textures
Black Linen 2 #103
 Dark  CC BY-SA 3.0

A new take on the black linen pattern. Softer this time.

Source Atle Mo

Retro Circles Background 4@2X #421
 Dark  CC 0

Retro Circles Background 4

Source GDJ

Fake Brick #358
 Dark  CC BY-SA 3.0

Black, simple, elegant, and useful.

Source Marat

Stucco #294
 Wall  CC BY-SA 3.0

A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.

Source Bartosz Kaszubowski

Prismatic Abstract Line Art Pattern Background 2 #567
 Dark  CC 0

Prismatic Abstract Line Art Pattern Background 2

Source GDJ

Pattern generator #161
 Noise  CC 0

A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.

Source Lazur URH

Cross Stripes@2X #48
 Dark  CC BY-SA 3.0

Nice and simple crossed lines in dark gray tones.

Source Stefan Aleksić

Prismatic Curved Diamond Pattern 7 No Background #547
 Noise  CC 0

Prismatic Curved Diamond Pattern 7 No Background

Source GDJ

Prismatic Polka Dots Mark II No Background@2X #531
 Noise  CC 0

Prismatic Polka Dots Mark II No Background

Source GDJ

Floral background 20 #1813
 Red  CC 0

Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885

Source Firkin

Background pattern 251 #2167
 Dark  CC 0

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

Source Firkin