Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. Version with black background.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
A bit of scratched up grayness. Always good.
Source Dmitry
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin