From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Black brick wall pattern. Brick your site up!
Source Alex Parker
Prismatic Abstract Geometric Background 5
Source GDJ
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Abstract Tiled Background Extended 12
Source GDJ
The image depicts a tiled seamless pattern.The tile represents four leaves aligned every 90 ° , which may look like a bird or a dragon .The original leaf design is from a Japanese old book.
Source Yamachem
The image is a design of blue glass.How about using it as background image?
Source Yamachem
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
The image depicts a seamless pattern of a snow crystal.I referred to a book called ”sekka-zusetsu” or "雪華図説" which means an illustrated explanation about snow crystals.This book was published in 1832 (天保3年) or Edo period.For more about "雪華図説",see here:dl.ndl.go.jp/info:ndljp/pid/2536975
Source Yamachem
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors