A cute x, if you need that sort of thing.
Source Juan Scrocchi
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
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
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
Inspired by an image that was uploaded to Pixabay by geralt
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin