Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
8 by 8 pixels, and just what the title says.
Source pixilated
Prismatic Polka Dots 3 No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin