Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
The perfect pattern for all your blogs about type, or type-related matters.
Source Atle Mo
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Sometimes you just need the simplest thing.
Source Fabricio
Prismatic Abstract Geometric Background 4
Source GDJ
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko