Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Prismatic Snowflakes Pattern No Background
Source GDJ
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
"Beige Stone", Tileable Texture.
Source V. Hartikainen
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Just like the black maze, only in light gray. Duh.
Source Peax
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Spice up your next school project with this icon background.
Source Swetha
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
A seamless pattern of leopard skin. It should look nice as a background element on web pages.
Source V. Hartikainen
A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
A seamless texture of a rough concrete surface.
Source V. Hartikainen