A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Colourful background achieved with gradient fills.
Source Firkin
Black And White Floral Pattern Background Inverse
Source GDJ
Alternative colour scheme for the original floral pattern.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Old China with a modern twist, take two.
Source Adam Charlts
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Fix and cc0 to get the tile this is based on.
Source SliverKnight
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
Prismatic Groovy Concentric Background 5
Source GDJ
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
8 by 8 pixels, and just what the title says.
Source pixilated
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen