I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Remixed from a drawing in 'An Index to Deering's Nottinghamia Vetus et Nova', Rupert Chicken, 1899. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Can’t believe we don’t have this in the collection already! Slick woven pattern with crisp details.
Source Max Rudberg
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
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 yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
A comeback for you: the popular Escheresque, now in black.
Source Patten
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Seamless Light Background Texture.
Source V. Hartikainen
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin