CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.
Source Yamachem
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
A new take on the black linen pattern. Softer this time.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen