The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
A free repetitive background with a dark concrete wall like texture. This one may be used in dark web site designs.
Source V. Hartikainen
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
A seamless background texture of old cardboard.
Source V. Hartikainen
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin