I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
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
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
A white version of the very popular linen pattern.
Source Ant Ekşiler
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Sometimes you just need the simplest thing.
Source Fabricio
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ