Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
This is the remix of "blue wave-seigaiha".The image depicts a seamless pattern of the front upper part of Japanese five yen coin which is used currently.This design represents a rice with ripe golden ears.
Source Yamachem
This one is amazing, truly original. Go use it!
Source Viahorizon
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
A seamless canvas texture for using as background on websites. Colored in pale tones of brown.
Source V. Hartikainen
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
A new one called white wall, not by me this time.
Source Yuji Honzawa
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Triangular Background Design Mark II 5
Source GDJ