This is sort of fresh, but still feels a bit old school.
Source Martuchox
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
You may use it as is, or modify it as you like.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
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
This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Subtle scratches on a light gray background.
Source Andrey Ovcharov
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Prismatic Groovy Concentric Background 3
Source GDJ
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin