Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Colourful background achieved with gradient fills.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
From an image on opengameart.org shared by rubberduck.
Source Firkin
A floral background formed from numerous clones of flower 117.
Source Firkin
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
Source Firkin
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Colour version of the original seamless pattern.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen