This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Background formed from the original with an emboss effect.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin