A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
Prismatic Groovy Concentric Background 5
Source GDJ
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk