This was formed by distorting an image of a background on Pixabay.
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Sharp pixel pattern, just like the good old days.
Source Paridhi
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
Abstract Stars Geometric Pattern Prismatic 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
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Tiny circle waves, almost like the ocean.
Source Sagive
Geometric triangles seem to be quite hot these days.
Source Pixeden
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Continuing the geometric trend, here is one more.
Source Mike Warner