To get the repeating unit, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green