Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
A version without colours blended together to give a different look.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
A repeating background with a look of paper. I have added some changes to PatCreator. Now you can share your designs by submitting them to a new gallery section. Start by clicking Edit with PatCreator above.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin