Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Prismatic Floral Background No Black
Source GDJ
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A comeback for you: the popular Escheresque, now in black.
Source Patten
A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Prismatic Geometric Pattern Background 2
Source GDJ
From a drawing in 'La Principauté de Liège et les Pays-Bas au XVIe siècle', Société des Bibliophiles Liégeois ,1887.
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin