Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
You may use it as is, or modify it as you like.
Source V. Hartikainen
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
A version without colours blended together to give a different look.
Source Firkin
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
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
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo