Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Hexagonalism Pattern No Background
Source GDJ
You may use it as is, or modify it as you like.
Source V. Hartikainen
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Number 3 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Colorful Floral Background 3 No Black
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
Spice up your next school project with this icon background.
Source Swetha
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin