A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
A seamless pattern based on a tile that can be achieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
CC0 and seamless wellington boot pattern.
Source SliverKnight
This is sort of fresh, but still feels a bit old school.
Source Martuchox
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Pattern produced in Paint.net using the Vibrato plug-in.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin