A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
A version without colours blended together to give a different look.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Prismatic Abstract Geometric Background 5
Source GDJ
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A web texture of brown canvas. Will look great, when used in dark web designs.
Source V. Hartikainen
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
One can never have too few rice paper patterns, so here is one more.
Source Atle Mo
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
One more sharp little tile for you. Subtle circles this time.
Source Blunia