Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A repeating background of thick textured paper. Actually, it turned out to look like something between a paper and fabric.
Source V. Hartikainen
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Inspired 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
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Prismatic Geometric Pattern Background
Source GDJ
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
Seamless Light Background Texture.
Source V. Hartikainen
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Element of beach pattern with background.
Source Rones
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
Prismatic Abstract Geometric Background 4
Source GDJ
Prismatic Groovy Concentric Background 3
Source GDJ