Stone Wall & Dark #1526
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

 More Textures
Stone Wall & Yellow #1578
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Background pattern 306 (colour 6) #1878
 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

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

Prismatic Abstract Geometric Background 5 #401
 Noise  CC 0

Prismatic Abstract Geometric Background 5

Source GDJ

Flourish pattern #1736
 Dark  CC 0

Remixed from an image that was uploaded to Pixabay by Pixeline

Source Firkin

Redox 01 #849
 Light  CC BY-SA 3.0

Bright gray tones with a hint of some metal surface.

Source Hendrik Lammers

Lego background #266
 Noise  CC 0

Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.

Source Firkin

Colourful background #2011
 Colorful  CC 0

Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic

Source Firkin

Scribble Light #739
 Paper  CC BY-SA 3.0

A bit like smudged paint or some sort of steel, here is scribble light.

Source Tegan Male

Dungeons & Flagons 2 #1418
 Diamond  CC 0

Gamedev - Floors Textures. CC0 License.

Source Davit Masia

Lined Paper #1034
 Light  CC BY-SA 3.0

I know there is one here already, but this is sexy!

Source Gjermund Gustavsen

Floral design 101 (version 2) #1757
 Green  CC 0

From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.

Source Firkin

Bark #1291
 Wall  CC 0

Zero CC tileable bark texture, photographed and made by me. CC0

Source Sojan Janso

[email protected] #736
 Light  CC BY-SA 3.0

A playful triangle pattern with different shades of gray.

Source Dimitrie Hoekstra

Wavy background #2013
 Pink  CC 0

A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic

Source Firkin

Retro Squares Background [email protected] #795
 Dark  CC 0

Retro Squares Background 9

Source GDJ

Stone Wall & Green #1532
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Stone Wall & Dark #1521
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Dark Brown Wood Pattern #884
 Wood  CC BY-SA 3.0

A seamless background pattern of dark brown wood planks.

Source V. Hartikainen

Prismatic Triangular Background Design Mark II 5 #406
 Dark  CC 0

Prismatic Triangular Background Design Mark II 5

Source GDJ

Hibiscus Flowers Seamless Background #229
 Fabric  CC 0

PDP

Source GDJ

Debut [email protected] #1015
 Dark  CC BY-SA 3.0

Same classic 45-degree pattern, dark version.

Source Luke McDonald

Decorative divider 241 #2084
 Dark  CC 0

From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.

Source Firkin

Floral divider 2 #1924
 Dark  CC 0

From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.

Source Firkin

Background pattern 242 #2203
 Red  CC 0

Random colour tile.

Source Firkin

Retro Circles Background 4 No Black #422
 Dark  CC 0

Retro Circles Background 4 No Black

Source GDJ

Decorative divider 243 #2082
 Dark  CC 0

From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.

Source Firkin

Prismatic Geometric Tessellation Pattern 4 No Background #557
 Noise  CC 0

Prismatic Geometric Tessellation Pattern 4 No Background

Source GDJ