This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
8 by 8 pixels, and just what the title says.
Source pixilated
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
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
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Prismatic Groovy Concentric Background 4
Source GDJ
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo