The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Sort of reminds me of those old house wallpapers.
Source Tish