Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
Prismatic Abstract Geometric Background 4
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Seamless Olive Green Web Background Image
Source V. Hartikainen
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
The image depicts a seamless pattern which includes hexagonally-aligned gourds with BG in light-brown.
Source Yamachem
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin