A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Prismatic Hexagonalist Pattern No Background
Source GDJ
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Green Web Background, Seamless tile.
Source V. Hartikainen
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin