Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
A new one called white wall, not by me this time.
Source Yuji Honzawa
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Prismatic Groovy Concentric Background 2
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Seamless SVG vector and JPG backgrounds with faded diagonal stripes. The colors are editable.
Source V. Hartikainen
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Sometimes you just need the simplest thing.
Source Fabricio
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Awesome name, great pattern. Who does not love space?
Source Nick Batchelor
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
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 pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Derived from a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin