Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Green Web Background, Seamless tile.
Source V. Hartikainen
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry
A version without colours blended together to give a different look.
Source Firkin
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Colorful Floral Background No Black
Source GDJ
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Black brick wall pattern. Brick your site up!
Source Alex Parker
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Spice up your next school project with this icon background.
Source Swetha
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac