Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
The image depicts polka dot seamless pattern.
Source Yamachem
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Abstract Tiled Background Extended 12
Source GDJ
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay