Old Mathematics@2X #44
 Stripes  CC BY-SA 3.0

This one takes you back to math class. Classic mathematic board underlay.

Source Josh Green

 More Textures
Background pattern green #1953
 Green  CC 0

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

Source Firkin

Faded Yellow Stripes, Background Pattern #933
 Stripes  CC BY-SA 3.0

A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.

Source V. Hartikainen

Fabric pattern 3 (colour 5) #2383
 Fabric  CC 0

Alternative colour scheme. 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

Floral Abstract Pattern Background #217
 Noise  CC 0

PDP

Source GDJ

Gun Metal@2X #361
 Dark  CC BY-SA 3.0

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

Source Nikolay Boltachev

Prismatic Diamond Background 6 #383
 Diamond  CC 0

Prismatic Diamond Background 6

Source GDJ

Prismatic Pointers Background #388
 Noise  CC 0

Prismatic Pointers Background

Source GDJ

Background pattern 223 (colour 5) #2349
 Blue  CC 0

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

Source Firkin

paper filer pack 2 #140
 Noise  CC 0

A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.

Source Lazur URH

Foggy Birds #579
 Light  CC BY-SA 3.0

Hey, you never know when you’ll need a bird pattern, right?

Source Pete Fecteau

Dark Stripes #39
 Dark  CC BY-SA 3.0

Very dark pattern with some noise and 45-degree lines.

Source Stefan Aleksić

Background pattern 10 #216
 Noise  CC 0

A pattern drawn in Paint.net and vectorized in Vector Magic.

Source Firkin

Dark Wood@2X #321
 Wood  CC BY-SA 3.0

A beautiful dark wood pattern, superbly tiled.

Source Omar Alvarado

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

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

Source pixilated

Old Wall #346
 Wall  CC BY-SA 3.0

Old concrete wall in light shades.

Source Bartosz Kaszubowski

Subtle Striped Brown Background Pattern #940
 Stripes  CC BY-SA 3.0

Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.

Source V. Hartikainen