Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Geometric triangles seem to be quite hot these days.
Source Pixeden
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Abstract Geometric Background 4
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
The image is a design of blue glass.How about using it as background image?
Source Yamachem
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
You guessed it – looks a bit like cloth.
Source Peax Webdesign
A seamless pattern formed from a rectangular tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Prismatic Hexagonalism Pattern No Background
Source GDJ
Prismatic Polka Dots 3 No Background
Source GDJ
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal