A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Psychedelic Geometric Background No Black
Source GDJ
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Spice up your next school project with this icon background.
Source Swetha
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Background formed from the original with an emboss effect.
Source Firkin
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The original has been presented as black on transparent and stored in the pattern definitions. To retrieve the unit tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
Original minus the background
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo