Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Geometric Pattern Background No Black
Source GDJ
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Black And White Floral Pattern Background from PDP.
Source GDJ
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes