A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
A lot of people like the icon patterns, so here’s one for your restaurant blog.
Source Andrijana Jarnjak
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
Background formed from the original with an emboss effect
Source GDJ
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
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