To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Seamless Light Background Texture.
Source V. Hartikainen
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.
Source Atle Mo
To get the repeating unit, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers