I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Element of beach pattern with background.
Source Rones
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Fix side and a seamless pattern formed from circles.
Source SliverKnight
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by k_jprather
Source Firkin
A white version of the very popular linen pattern.
Source Ant Ekşiler
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen