Wavy background #2023
Pink CC 0CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
More Textures
Prismatic Isometric Cube Extra Pattern No Background@2X #789
Light CC 0Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
crissXcross@2X #112
Dark CC BY-SA 3.0Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Diagonal Waves #1006
Gray CC BY-SA 3.0It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Prismatic Curved Diamond Pattern 3 No Background@2X #540
Diamond CC 0Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Repeating Wood Straw Background #887
Wood CC BY-SA 3.0A repeating background with wood/straw like texture.
Source V. Hartikainen
Background pattern 261 #2076
Dark CC 0Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
Green and Yellow Lines on White Background #1000
Stripes CC BY-SA 3.0A seamless pattern with green and yellow diagonal lines on top of a white dotted background.
Source V. Hartikainen
Background Patterns - Aubergine #247
Fabric CC 0If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Wood Pattern #370
Wood CC BY-SA 3.0One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Page ornament #1993
Dark CC 0From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Mooning #1140
Gray CC BY-SA 3.0The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Pattern #1476
Paper CC 0Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
Batthern #324
Grid CC BY-SA 3.0Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Fabric pattern 3 (colour 2) #2386
Fabric CC 0Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
seigaiha subtle color #2278
Pink CC 0This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Prismatic Groovy Concentric Background 4 No Black #463
Noise CC 0Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Prismatic Geometric Tessellation Pattern 2 No Background #553
Noise CC 0Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
Prismatic Chevrons Pattern 5 With Background #469
Dark CC 0Prismatic Chevrons Pattern 5 With Background
Source GDJ
Background pattern blue #1955
Blue CC 0To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin