A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Tile available in Inkscape using shift-alt-i on the selected rectangle
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
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Used the 6th circle pattern designed by Viscious-Speed to create a print that can be used for card making or scrapbooking. Save as a PDF file for the best printing option.
Source Lovinglf
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
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
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
ZeroCC tileable beechwood wood texture, generated in Neo Texture Edit by me. CC0
Source Sojan Janso
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin