A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
This one is amazing, truly original. Go use it!
Source Viahorizon
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin