This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Might not be super subtle, but quite original in its form.
Source Alex Smith
Green Web Background, Seamless tile.
Source V. Hartikainen
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
This light yellow background pattern consists of an irregular pattern of spots. Here's a light background pattern with yellowish tint.
Source V. Hartikainen
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
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin