This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
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
Kaleidoscope Prismatic Abstract No Background
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
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 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
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
This is sort of fresh, but still feels a bit old school.
Source Martuchox