From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
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
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg