I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
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
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Prismatic Abstract Background Design
Source GDJ
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso