As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Colour version of the original pattern.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Prismatic Groovy Concentric Background No Black
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
Element of beach pattern with background.
Source Rones
Remixed from a drawing in 'Incidents on a Journey through Nubia to Darfoor', F. Ensor, 1891.
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso