And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Found on the ground in french cafe in kunming, Yunnan, china
Source Rejon
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Prismatic Groovy Concentric Background 3
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Remixed from a drawing in 'Prehistoric Man: researches into the origin of civilisation in the old and the new world', Daniel Wilson, 1876.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso