A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
Seamless Light Background Texture.
Source V. Hartikainen
8 by 8 pixels, and just what the title says.
Source pixilated
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
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
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A heavy hitter at 400x400px, but lovely still.
Source Breezi
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin