Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen
This one needs to be used in small areas; you can see it repeat.
Source Luca
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso