Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Prismatic Groovy Concentric Background 4
Source GDJ
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC asphalt, pavement, texture, photographed and made by me. CC0 WARNING I FOUND A SEAM ON THIS TEXTURE
Source Sojan Janso
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
A version without colours blended together to give a different look.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel