Green Web Background, Seamless tile.
Source V. Hartikainen
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró
CC0 and seamless wellington boot pattern.
Source SliverKnight
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
A background tile for web with abstract repeating texture of dark "stone wall".
Source V. Hartikainen
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock