A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A green background pattern with warped vertical stripes and a grunge look.
Source V. Hartikainen
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
A seamless paper background colored in pale yellow.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
The image a seamless pattern of a wire-mesh fence.I want you to use this pattern as a lower layer.
Source Yamachem
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Prismatic Hexagonalist Pattern No Background
Source GDJ
Prismatic Groovy Concentric Background
Source GDJ
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
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
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Prismatic Geometric Pattern Background
Source GDJ
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Here's a new gray "fabric" pattern. Use it as backgrounds for websites or for other purposes.
Source V. Hartikainen