A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Prismatic Groovy Concentric Background 5
Source GDJ
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
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
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
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
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn