Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Clover with background for St. Patrick's Day. Add to a card with a doily, ribbon, a leprechaun or other embellishments.
Source BAJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
An alternative colour scheme to the original seamless pattern.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Fix and cc0 to get the tile this is based on.
Source SliverKnight
From a drawing in 'Less Black than we're painted', James Payn, 1884.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin