Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Embossed lines and squares with subtle highlights.
Source Alex Parker
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
This is the remix of "plant pattern 02".I changed the object color to white and the BG to purple.The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:jp.pinterest.com/pin/500744052301423641/
Source Yamachem
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
I’m not going to lie – if you submit something with the words Norwegian and Rose in it, it’s likely I’ll publish it.
Source Fredrik Scheide
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
This white background pattern has a seamless grunge style texture. Here's a white grunge style background pattern. Use it as a tiled background image on web sites or for other purposes.
Source V. Hartikainen
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Might not be super subtle, but quite original in its form.
Source Alex Smith
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
This is the remix of "Strawberry Pattern Background" uploaded by "GDJ". Thanks. I realigned strawberries so as to get seamless and changed the BG color.
Source Yamachem
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen