Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
8 by 8 pixels, and just what the title says.
Source pixilated
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A background pattern with green vertical stripes. A new striped background pattern. This time a green one.
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
No, not the band but the pattern. Simple squares in gray tones, of course.
Source Atle Mo
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov