Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Prismatic Polka Dots 3 No Background
Source GDJ
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A blue gray fabric-like texture for websites. An yet another fabric-like texture. It has subtle vertical and diagonal stripes to it.
Source V. Hartikainen
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
This is a remix of "geometrical pattern 01".
Source Yamachem
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Snowflakes Pattern No Background
Source GDJ
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 heavy hitter at 400x400px, but lovely still.
Source Breezi
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin