More Textures
Noisy #45
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic

Pinetree in tortoiseshell(亀甲松) #2538
 Dark  CC 0

The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/

Source Yamachem

Background pattern 105 #563
 Dark  CC 0

A seamless pattern formed from background pattern 102

Source Firkin

Floral background 20 #1813
 Red  CC 0

Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885

Source Firkin

Prismatic Groovy Concentric Background 3 No Black@2X #460
 Noise  CC 0

Prismatic Groovy Concentric Background 3 No Black

Source GDJ

Background pattern pink and colours #2032
 Colorful  CC 0

A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.

Source Firkin

Old Mathematics #43
 Stripes  CC BY-SA 3.0

This one takes you back to math class. Classic mathematic board underlay.

Source Josh Green

Background pattern 230 (colour 2) #2302
 Green  CC 0

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

Source Firkin

Seamless Colorful Floral Pattern Background #256
 Fabric  CC 0

PDP

Source GDJ

Prismatic Geometric Pattern Background No Black #408
 Noise  CC 0

Prismatic Geometric Pattern Background No Black

Source GDJ