CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Prismatic Groovy Concentric Background
Source GDJ
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Groovy Concentric Background 2
Source GDJ
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
A heavy hitter at 400x400px, but lovely still.
Source Breezi
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida