Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Abstract Ellipses Background Grayscale
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A seamless background of warped stripes on paper.
Source V. Hartikainen
Continuing the geometric trend, here is one more.
Source Mike Warner
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
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
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
This is a remix of "geometrical pattern 01".
Source Yamachem