A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
White circles connecting on a light gray background.
Source Mark Collins
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
A free pink background pattern.
Source V. Hartikainen
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
This one needs to be used in small areas; you can see it repeat.
Source Luca
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
A seamless stone-like background for blogs or any other type of websites.
Source V. Hartikainen
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin