From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
Colorful Floral Background 3 No Black
Source GDJ
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Subtle scratches on a light gray background.
Source Andrey Ovcharov
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH