A comeback for you: the popular Escheresque, now in black.
Source Patten
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
A repeating background with wood/straw like texture.
Source V. Hartikainen
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
You know you love wood patterns, so here’s one more.
Source Richard Tabor
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Gold Triangular Seamless Pattern No Background
Source GDJ
Prismatic Hexagonalism Pattern No Background
Source GDJ
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Prismatic Abstract Background Design No Black
Source GDJ
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Seamless Olive Green Web Background Image
Source V. Hartikainen
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8