I’m starting to think I have a concrete wall fetish.
Source Atle Mo
Prismatic Hexagonalist Pattern No Background
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Plywood Web Background background image for use in web design.
Source V. Hartikainen
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
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek