As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Background pattern made in "Grunge-Like" style. Available in both SVG and JPG formats. Edit to your needs then click the download button.
Source V. Hartikainen
Continuing the geometric trend, here is one more.
Source Mike Warner
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Used the 6th circle pattern designed by Viscious-Speed to create a print that can be used for card making or scrapbooking. Save as a PDF file for the best printing option.
Source Lovinglf
Number 2 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
Prismatic Geometric Pattern Background No Black
Source GDJ
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin