Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
From a drawing in 'Jardyne's Wife', Charles Wills, 1891.
Source Firkin
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
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
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Prismatic Polka Dots 3 No Background
Source GDJ
The following orange background pattern resembles a honeycomb.
Source V. Hartikainen
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Prismatic Polyskelion Pattern No Background
Source GDJ
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Prismatic Groovy Concentric Background 4
Source GDJ
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Prismatic Groovy Concentric Background 4 No Black
Source GDJ