A seamless background of warped stripes on paper.
Source V. Hartikainen
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Seamless SVG vector and JPG backgrounds with faded diagonal stripes. The colors are editable.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
Prismatic Abstract Geometric Background 5
Source GDJ
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen