Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
A frame using leaves from an image that was uploaded to Pixabay by mayapujiati
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Sharp pixel pattern, just like the good old days.
Source Paridhi
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
From a drawing in 'Less Black than we're painted', James Payn, 1884.
Source Firkin
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
A floral background formed from numerous clones of flower 117.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Geometric Pattern Background No Black
Source GDJ