CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Derived from a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern formed from a rectangular tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The original enhanced with one of Inkscapes's filters.
Source Firkin
Zero CC tileable yellow craft paper; scanned and made by me. CC0
Source Sojan Janso
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Groovy Concentric Background
Source GDJ
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen