Seamless Core Pattern 3 #167
 Dark  CC 0

Seamless Core Pattern 3

Source GDJ

 More Textures
Grunge Wall #81
 Wall  CC BY-SA 3.0

Light gray grunge wall with a nice texture overlay.

Source Adam Anlauf

Colorful Floral Background@2X #480
 Noise  CC 0

Colorful Floral Background

Source GDJ

Retro Squares Background 8 #398
 Noise  CC 0

Retro Squares Background 8

Source GDJ

Background pattern 231 #2301
 Dark  CC 0

A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Background pattern 328 (colour 5) #1797
 Blue  CC 0

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

Source Firkin

Gray Sand #17
 Dark  CC BY-SA 3.0

A dark gray, sandy pattern with small light dots, and some angled strokes.

Source Atle Mo

Graphene pattern 2 #2234
 Dark  CC 0

Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Decorative divider 288 #1820
 Dark  CC 0

From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.

Source Firkin

Brushed Alum Dark #65
 Dark  CC BY-SA 3.0

Because I love dark patterns, here is Brushed Alum in a dark coating.

Source Tim Ward

Tessellation 16 #2215
 Yellow  CC 0

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

Source Firkin