This could be a hippy vintage wallpaper.
Source Tileable Patterns
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
The following orange background pattern resembles a honeycomb.
Source V. Hartikainen
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Prismatic Groovy Concentric Background 3
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.
Source V. Hartikainen
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin