A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Just like the black maze, only in light gray. Duh.
Source Peax
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
White handmade paper pattern with small bumps.
Source Marquis
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Prismatic Groovy Concentric Background 2
Source GDJ
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A seamless background tile of aged paper with shabby look.
Source V. Hartikainen
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso