Floral background 20 #1813
 Red  CC 0

Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885

Source Firkin

 More Textures
Dark Denim #29
 Dark  CC BY-SA 3.0

A dark denim looking pattern. 145×145 pixels.

Source Atle Mo

Robots@2X #126
 Dark  CC BY-SA 3.0

And some more testing, this time with Seamless Studio. It’s Robots FFS!

Source Seamless Studio

Tessellation 16 (colour 4) #2212
 Green  CC 0

The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.

Source Firkin

Colorful Floral Background 3 No Black #485
 Light  CC 0

Colorful Floral Background 3 No Black

Source GDJ

Background pattern 315 (colour 4) #1842
 Colorful  CC 0

The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Seamless Cardboard Texture #1212
 Cardboard  CC BY-SA 3.0

A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.

Source V. Hartikainen

Background Patterns - Ebony #249
 Fabric  CC 0

If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117

Source Viscious-Speed

Grunge Wall@2X #82
 Wall  CC BY-SA 3.0

Light gray grunge wall with a nice texture overlay.

Source Adam Anlauf

Mosaic Gems Background@2X #527
 Noise  CC 0

Mosaic Gems Background

Source GDJ

Background pattern 104 #561
 Dark  CC 0

Background pattern 104

Source Firkin

Noisy@2X #46
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic

45-Degree Fabric@2X #2
 Fabric  CC BY-SA 3.0

Medium gray fabric pattern with 45-degree lines going across.

Source Atle Mo

Rocky Wall #41
 Wall  CC BY-SA 3.0

High detail stone wall with minor cracks and specks.

Source Projecteightyfive