The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A free web background image with a seamless concrete-like texture and an Indian-red color.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A brown metallic grid pattern layered on top of a dark fabric texture. It should look great when using as a tiled background on web pages, especially blogs.
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Prismatic Polka Dots Mark II No Background
Source GDJ
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Embossed lines and squares with subtle highlights.
Source Alex Parker
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Retro Circles Background 7 No Black
Source GDJ
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel