Basket Fibers, Basket Texture, Braid Background style CC0 texture.
Source 1A-Photoshop
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Abstract Ellipses Background Grayscale
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Remixed from a drawing in 'Jezebel's Daughter', Wilkie Collins 1880
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
A seamless pattern formed from background pattern 102
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars