Background Patterns - Slate #244
 Fabric  CC 0

If you want png files of thisu can download them here :

Source Viscious-Speed

 More Textures
Soft Circle Scales@2X #114
 Light  CC BY-SA 3.0

Japanese looking fish scale pattern.

Source Ian Soper

Prismatic Geometric Pattern Variation 2 With Background@2X #472
 Noise  CC 0

Prismatic Geometric Pattern Variation 2 With Background

Source GDJ

Decorative divider 293 #1752
 Dark  CC 0

From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.

Source Firkin

Background pattern blue #1940
 Blue  CC 0

Formed by heavily distorting part of a an image of a fish uploaded to Pixabay by GLady

Source Firkin

Background pattern 336 (colour 2) #1720
 Green  CC 0

Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.

Source Firkin

Background pattern 306 (colour 4) #1877
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin

Prismatic Dots Background 8 #515
 Noise  CC 0

Prismatic Dots Background 8

Source GDJ

Cardboard #278
 Paper  CC BY-SA 3.0

A good starting point for a cardboard pattern. This would work well in a variety of colors.

Source Atle Mo

Prismatic Rounded Squares Grid 3 No Background@2X #490
 Noise  CC 0

Prismatic Rounded Squares Grid 3 No Background

Source GDJ