Merely Cubed@2X #590
 Grid  CC BY-SA 3.0

Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.

Source Etienne Rallion

 More Textures
Background pattern 259 #2133
 Red  CC 0

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

Prismatic Geometric Pattern Background #407
 Noise  CC 0

Prismatic Geometric Pattern Background

Source GDJ

Squares@2X #303
 Dark  CC BY-SA 3.0

Dark, square, clean and tidy. What more can you ask for?

Source Jaromír Kavan

Background pattern 18 #202
 Dark  CC 0

A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.

Source Firkin

Repeating Website Background (Blue Gray) #1192
 Concrete  CC BY-SA 3.0

The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.

Source V. Hartikainen

Background cubic #238
 Dark  CC 0

Fondo en falsa perpectiva

Source Roshellin

Stripy checkerboard pattern 2 #1767
 Dark  CC 0

Simple combination of stripy squares with their negatively coloured counterparts

Source Firkin

Light Grey Floral Motif@2X #345
 Wall  CC BY-SA 3.0

Lovely light gray floral motif with some subtle shades.

Source GraphicsWall

Background pattern 221 (colour) #2346
 Yellow  CC 0

A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Square ornament 38 #2147
 Dark  CC 0

From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.

Source Firkin

Background pattern 248 #2181
 Dark  CC 0

To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.

Source Firkin