Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Background formed from the original with an emboss effect.
Source Firkin
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
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
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee