A simple bump filter made upon request at irc #inkscape at freenode. Made a screen capture of the making here: https://youtu.be/TGAWYKVLxQw
Source Lazur URH
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Embossed lines and squares with subtle highlights.
Source Alex Parker
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
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
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin