Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
A comeback for you: the popular Escheresque, now in black.
Source Patten
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
Prismatic Hypnotic Pattern No Background
Source GDJ
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
A seamless texture of worn out "cardboard".
Source V. Hartikainen
This seamless web background texture looks like gray stone. It's great for using as a background image on web pages, or on some of their elements. Anyway, I hope you will find use for it.
Source V. Hartikainen