The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Light and tiny, just the way you like it.
Source Rohit Arun Rao
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless pattern of dark bricks. Maybe it's not very realistic, but it looks good in my opinion.
Source V. Hartikainen
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
A white version of the very popular linen pattern.
Source Ant Ekşiler
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
Zero CC asphalt, pavement, texture, photographed and made by me. CC0 WARNING I FOUND A SEAM ON THIS TEXTURE
Source Sojan Janso
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ