A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Remixed from a drawing in 'Jezebel's Daughter', Wilkie Collins 1880
Source Firkin
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
A bit strange this one, but nice at the same time.
Source Diogo Silva
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker