This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
The image depicts a seamless pattern of the design which includes a stylized lotus and a stylized crane.I referred to the original image in a book which is into public domain.
Source Yamachem
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
An abstract texture of black metal pipes (seamless).
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
Prismatic Polka Dots 3 No Background
Source GDJ
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
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