Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Prismatic Abstract Geometric Background 5
Source GDJ
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Prismatic Polyskelion Pattern No Background
Source GDJ
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zero CC tileable hard cover green book, scanned and made by me. CC0
Source Sojan Janso
An alternative colour scheme for the original background.
Source Firkin
Prismatic Abstract Background Design
Source GDJ
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic