I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Colourful background achieved with gradient fills.
Source Firkin
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
Prismatic Abstract Line Art Pattern Background
Source GDJ
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. A version of the original with random colors.
Source Firkin
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
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
A seamless paper background colored in pale yellow.
Source V. Hartikainen
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin