Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
The image depicts a seamless pattern of the design which includes a stylized lotus and a stylized crane.I referred to the original image in a book which is into public domain.
Source Yamachem
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Retro Circles Background 8 No Black
Source GDJ
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Black And White Floral Pattern Background from PDP.
Source GDJ
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
This pattern comes in orange, and it looks as if it is "made of glass".
Source V. Hartikainen
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
This one needs to be used in small areas; you can see it repeat.
Source Luca
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle