As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
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
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A green background pattern with warped vertical stripes and a grunge look.
Source V. Hartikainen
A heavy hitter at 400x400px, but lovely still.
Source Breezi
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
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen