Background pattern 306 (colour 4) #1877
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin

 More Textures
Background pattern 215 (colour 3) #2369
 Pink  CC 0

A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.

Source Firkin

Prismatic Arrows Background 2 #393
 Light  CC 0

Prismatic Arrows Background 2

Source GDJ

Background pattern 309 (colour 4) #1863
 Green  CC 0

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

Source Firkin

Small Crosses@2X #116
 Stripes  CC BY-SA 3.0

Sharp pixel pattern looking like some sort of fabric.

Source Dmitry

Dotnoise Light Grey@2X #309
 Wall  CC BY-SA 3.0

Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!

Source Nikolalek

Medic Packaging Foil@2X #377
 Light  CC BY-SA 3.0

8 by 8 pixels, and just what the title says.

Source pixilated

Dark Mosaic #121
 Dark  CC BY-SA 3.0

Small dots with minor circles spread across to form a nice mosaic.

Source John Burks

Paisley Background #495
 Light  CC 0

Paisley Background

Source GDJ

Retro Circles Background 7 #431
 Unknow  CC 0

Retro Circles Background 7

Source GDJ