A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
Dark blue concrete wall with some small dust spots.
Source Atle Mo
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Inspired by a JPG that was uploaded to Pixabay by kokon_art
Source Firkin
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Prismatic Geometric Tessellation Pattern No Background
Source GDJ