Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
I love the movie Pineapple Express, and I’m also liking this Pineapple right here.
Source Audee Mirza
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
Prismatic Hexagonalism Pattern No Background
Source GDJ
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Psychedelic Geometric Background No Black
Source GDJ
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen