Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
Prismatic Abstract Geometric Background 4
Source GDJ
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
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
You know you love wood patterns, so here’s one more.
Source Richard Tabor
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Seamless Prismatic Geometric Pattern With Background
Source GDJ
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
A repeating background of thick textured paper. Actually, it turned out to look like something between a paper and fabric.
Source V. Hartikainen
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Seamless Prismatic Quadrilateral Line Art Pattern No Background
Source GDJ