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
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
An alternative colour scheme to the original seamless pattern.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
An aged paper background tile with smeared and pressed text.
Source V. Hartikainen
A version without colours blended together to give a different look.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin