Colourful background #2011
 Colorful  CC 0

Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic

Source Firkin

 More Textures
Seamless Colorful Floral Pattern Background #256
 Fabric  CC 0

PDP

Source GDJ

Polaroid@2X #188
 Wall  CC BY-SA 3.0

Smooth Polaroid pattern with a light blue tint.

Source Daniel Beaton

Background pattern 227 (colour 5) #2310
 Colorful  CC 0

A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.

Source Firkin

Spirals pattern #1994
 Colorful  CC 0

Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i

Source Firkin

Always Grey #53
 Dark  CC BY-SA 3.0

Crossing lines with a subtle emboss effect on a dark background.

Source Stefan Aleksić

Green Gobbler #85
 Dark  CC BY-SA 3.0

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

Source Simon Meek

Prismatic Groovy Concentric Background@2X #450
 Noise  CC 0

Prismatic Groovy Concentric Background

Source GDJ

Light Honeycomb@2X #60
 Light  CC BY-SA 3.0

Light honeycomb pattern made up of the classic hexagon shape.

Source Federica Pelzel

Background pattern 202 (colour 2) #2489
 Green  CC 0

Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i

Source Firkin

Pool Table@2X #176
 Wall  CC BY-SA 3.0

This makes me wanna shoot some pool! Sweet green pool table pattern.

Source Caveman

Gun Metal #360
 Dark  CC BY-SA 3.0

With a name this awesome, how can I go wrong?

Source Nikolay Boltachev