WaveCut #75
 Light  CC BY-SA 3.0

If you like it a bit trippy, this wave pattern might be for you.

Source Ian Soper

 More Textures
Prismatic Curved Diamond Pattern 2 No Background@2X #539
 Diamond  CC 0

Prismatic Curved Diamond Pattern 2 No Background

Source GDJ

Background cubic #238
 Dark  CC 0

Fondo en falsa perpectiva

Source Roshellin

Background pattern 223 (colour 2) #2352
 Blue  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