Green Gobbler@2X #86
 Dark  CC BY-SA 3.0

Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.

Source Simon Meek

 More Textures
Background pattern 309 (colour 2) #1865
 Blue  CC 0

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

Source Firkin

60º lines #25
 Light  CC BY-SA 3.0

Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.

Source Atle Mo

Background2 #259
 Wall  CC 0

rug texture background

Source Jilllio

Background pattern 225 (colour 3) #2325
 Pink  CC 0

Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

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

Fabric pattern 2 (colour 3) #2394
 Fabric  CC 0

Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Patchwork Quilt Pattern Background #228
 Noise  CC 0

PDP

Source GDJ

Black Mamba@2X #58
 Dark  CC BY-SA 3.0

The name alone is awesome, but so is this sweet dark pattern.

Source Federica Pelzel

Seamless Prismatic Pythagorean Line Art Pattern No Background #569
 Light  CC 0

Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).

Source GDJ

Prismatic Hypnotic Pattern 2 No Background #573
 Noise  CC 0

Prismatic Hypnotic Pattern 2 No Background

Source GDJ

Background pattern 8 (greyscale) #210
 Dark  CC 0

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

Source Firkin