The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Element of beach pattern with background.
Source Rones
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
Prismatic 3D Isometric Tessellation Pattern 6
Source GDJ
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Formed by distorting an image on Pixabay that was uploaded by gustavorezende. To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The name Paisley reminds me of an old British servant. That’s just me.
Source Swetha
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba