This could be a hippy vintage wallpaper.
Source Tileable Patterns
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Prismatic Groovy Concentric Background 3
Source GDJ
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Abstract Ellipses Background Grayscale
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
Prismatic Hexagonalism Pattern No Background
Source GDJ
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Prismatic Groovy Concentric Background No Black
Source GDJ
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
A new one called white wall, not by me this time.
Source Yuji Honzawa