Could be paper, could be a Polaroid frame – up to you!
Source Chaos
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
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
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
This is sort of fresh, but still feels a bit old school.
Source Martuchox
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
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 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 texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Could be paper, could be a Polaroid frame – up to you!
Source Chaos