An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Prismatic Hexagonalist Pattern No Background
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Similar to original, but without gaps in between the arrows. This seamless pattern was created from a rectangular tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Abstract Tiled Background Extended 6
Source GDJ
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Sharp but soft triangles in light shades of gray.
Source Pixeden
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens