A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Seamless Green Tile Background
Source V. Hartikainen
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Prismatic Abstract Background Design
Source GDJ
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
8 by 8 pixels, and just what the title says.
Source pixilated
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin