Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
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
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Remixed from an image that was uploaded to Pixabay by KirstenStar
Source Firkin
Geometric triangles seem to be quite hot these days.
Source Pixeden
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo