A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
A seamless marble-like texture colored in light blue.
Source V. Hartikainen
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
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 light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
Remixed from a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:https://jp.pinterest.com/pin/500744052301423641/
Source Yamachem
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
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
A free pink background pattern.
Source V. Hartikainen
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran