The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Clover with background for St. Patrick's Day. Add to a card with a doily, ribbon, a leprechaun or other embellishments.
Source BAJ
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Prismatic Abstract Geometric Background 5
Source GDJ
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
A floral background formed from numerous clones of flower 117.
Source Firkin
The image depicts a tiled seamless pattern.The tile represents four leaves aligned every 90 ° , which may look like a bird or a dragon .The original leaf design is from a Japanese old book.
Source Yamachem
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman