Tessellation 16 (colour 6) #2210
 Colorful  CC 0

The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i

Source Firkin

 More Textures
Fabric 1@2X #10
 Light  CC BY-SA 3.0

Semi-light fabric pattern made out of random pixels in shades of gray.

Source Atle Mo

Black Mamba #57
 Dark  CC BY-SA 3.0

The name alone is awesome, but so is this sweet dark pattern.

Source Federica Pelzel

Connected@2X #349
 Light  CC BY-SA 3.0

White circles connecting on a light gray background.

Source Mark Collins

Prismatic Groovy Concentric Background 3 No Black #459
 Noise  CC 0

Prismatic Groovy Concentric Background 3 No Black

Source GDJ

Background pattern 256 (colour) #2138
 Red  CC 0

Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i

Source Firkin

Concrete Wall 2@2X #80
 Wall  CC BY-SA 3.0

A light gray wall or floor (you decide) of concrete.

Source Atle Mo

Background pattern 224 (colour 2) #2341
 Colorful  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.

Source Firkin

Black Linen 2 #103
 Dark  CC BY-SA 3.0

A new take on the black linen pattern. Softer this time.

Source Atle Mo

Bright Multicolored Floral Background@2X #560
 Noise  CC 0

Bright Multicolored Floral Background by Karen Arnold from PDP.

Source GDJ

Background pattern 315 (colour 2) #1844
 Red  CC 0

The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Background pattern 223 (colour 6) #2348
 Yellow  CC 0

Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

Xv@2X #315
 Paper  CC BY-SA 3.0

Floral patterns will never go out of style, so enjoy this one.

Source Lasma