Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
Prismatic Groovy Concentric Background No Black
Source GDJ
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
White circles connecting on a light gray background.
Source Mark Collins