The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
Prismatic Hexagonalism Pattern No Background
Source GDJ
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
A frame using leaves from an image that was uploaded to Pixabay by mayapujiati
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless tessellation pattern. To get the tile this is formed from, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
The base gradient edited so now more details are rendered.
Source Lazur URH
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Prismatic Abstract Geometric Background 4
Source GDJ
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The following free background pattern has glossy diagonal stripes as a texture to it, and it's colored in a light blue gray color. This background pattern is suitable for using in web design or any other graphic design projects. This applies to all background patterns here.
Source V. Hartikainen
From an image on opengameart.org shared by rubberduck.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos