The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
The original has been presented as black on transparent and stored in the pattern definitions. To retrieve the unit tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin