If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.
Source Firkin
A gray background pattern with a texture of textile. Suits perfectly for web design.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Colour version of the original pattern.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin