A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
The image depicts a seamless pattern which includes hexagonally-aligned gourds with BG in light-brown.
Source Yamachem
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Fix side and a seamless pattern formed from circles.
Source SliverKnight
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin