A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
8 by 8 pixels, and just what the title says.
Source pixilated