Graphy #350
 Grid  CC BY-SA 3.0

Looks like a technical drawing board: small squares forming a nice grid.

Source We Are Pixel8

 More Textures
Seamless Core Pattern 5 #169
 Dark  CC 0

Seamless Core Pattern 5

Source GDJ

Prismatic Geometric Tessellation Pattern 3 No Background #555
 Noise  CC 0

Prismatic Geometric Tessellation Pattern 3 No Background

Source GDJ

Prismatic Chevrons Pattern 5 With Background #469
 Dark  CC 0

Prismatic Chevrons Pattern 5 With Background

Source GDJ

Soft Wallpaper #95
 Wall  CC BY-SA 3.0

Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.

Source Atle Mo

Shapes pattern #2409
 Brown  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

"Pink Bump Dots", Background Tile #1234
 Pink  CC BY-SA 3.0

A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.

Source V. Hartikainen

Background pattern 309 (colour 3) #1864
 Red  CC 0

Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.

Source Firkin

Prismatic Groovy Concentric Background 2 No Black@2X #456
 Noise  CC 0

Prismatic Groovy Concentric Background 2 No Black

Source GDJ

Decorative divider 228 #2154
 Dark  CC 0

Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.

Source Firkin

Patchwork Quilt Pattern Background #228
 Noise  CC 0

PDP

Source GDJ

Prismatic Geometric Tessellation Pattern No Background@2X #552
 Noise  CC 0

Prismatic Geometric Tessellation Pattern No Background

Source GDJ

Diamond pattern 2 (colour 6) #2261
 Colorful  CC 0

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

Source Firkin