Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Classic vertical lines, in all its subtlety.
Source Cody L
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
A seamless tessellation pattern. To get the tile this is formed from, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
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
Retro Circles Background 7 No Black
Source GDJ
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A seamless texture of a rough concrete surface.
Source V. Hartikainen
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss