Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Abstract Background Design
Source GDJ
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Prismatic Floral Background No Black
Source GDJ