From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
A seamless background texture of old cardboard.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Prismatic Groovy Concentric Background 2
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
You may use it as is, or modify it as you like.
Source V. Hartikainen
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin