A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
A seamless paper background colored in pale yellow.
Source V. Hartikainen
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin