Sometimes you just need the simplest thing.
Source Fabricio
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
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
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
The name is totally random, but hey, it sounds good.
Source Atle Mo
Prismatic Hypnotic Pattern 2 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 light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen