The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
A blue gray fabric-like texture for websites. An yet another fabric-like texture. It has subtle vertical and diagonal stripes to it.
Source V. Hartikainen
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
One more sharp little tile for you. Subtle circles this time.
Source Blunia
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
The original enhanced with some gradients.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
There are many carbon patterns, but this one is tiny.
Source Designova
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin