This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
A free seamless background pattern for use on websites.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
Prismatic Groovy Concentric Background 5
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
It’s big, it’s gradient—and it’s square.
Source Brankic1979
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
8 by 8 pixels, and just what the title says.
Source pixilated
White circles connecting on a light gray background.
Source Mark Collins
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
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