From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin