A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Prismatic Floral Background No Black
Source GDJ
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic 3D Isometric Tessellation Pattern 6
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
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić