Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Adapted from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
This is a seamless pattern of a woody texture.The original image is here:https://pixabay.com/ja/users/ClassicallyPrinted-1302233/
Source Yamachem
Prismatic Abstract Geometric Background 5
Source GDJ
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Classic vertical lines, in all its subtlety.
Source Cody L
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee