A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Abstract Tiled Background Extended 11
Source GDJ
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
This one needs to be used in small areas; you can see it repeat.
Source Luca
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
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
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
A cute x, if you need that sort of thing.
Source Juan Scrocchi
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin