This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
You may use it as is, or modify it as you like.
Source V. Hartikainen
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
The base gradient edited so now more details are rendered.
Source Lazur URH
A seamless paper background texture colored in pale yellow. This seamless texture is ideal for those who need a yellow background image for their website. The texture resembles paper.
Source V. Hartikainen
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Prismatic Abstract Geometric Background 3
Source GDJ
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
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
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Continuing the geometric trend, here is one more.
Source Mike Warner
Prismatic Geometric Pattern Background No Black
Source GDJ
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Seamless Olive Green Web Background Image
Source V. Hartikainen