Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Seamless Light Background Texture.
Source V. Hartikainen
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
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
A blue background wallpaper for websites. It has a seamless texture with vertical stripes. It looks quite nice not only when using as a tiled background on websites, but also on computer desktops.
Source V. Hartikainen
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer