Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen
Prismatic Abstract Background Design No Black
Source GDJ
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics