The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
A seamlessly tile-able grunge background image.
Source V. Hartikainen
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Prismatic Floral Background No Black
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
This is sort of fresh, but still feels a bit old school.
Source Martuchox
An alternative colour scheme for the original seamless texture formed from an image on Pixabay.
Source Firkin
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Zero CC asphalt, pavement, texture, photographed and made by me. CC0 WARNING I FOUND A SEAM ON THIS TEXTURE
Source Sojan Janso
Continuing the geometric trend, here is one more.
Source Mike Warner
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin