A comeback for you: the popular Escheresque, now in black.
Source Patten
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
This is a remix of "flower seamless pattern".I rotated the original image by 90 degrees.This is a seamless pattern of flowers.These horizontal wavy lines are one of Edo patterns which is called "tatewaku or tachiwaku or 立湧" that represents uprising steam or vapor.
Source Yamachem
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
CC0 and seamless wellington boot pattern.
Source SliverKnight
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Prismatic Curved Diamond Pattern No Background
Source GDJ
The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Inspired by a design found in 'Konstantinápolyi emlékeim', Miklos Chriszto, 1893.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Background formed from the original with an emboss effect
Source GDJ
Someone was asking about how to achieve a fur pattern at #inkscape irc so tried to make a filter on it. Flood filled fractal noises rigged together. May someone find a good use for these.
Source Lazur URH
Prismatic Abstract Line Art Pattern Background 2
Source GDJ