The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Psychedelic Geometric Background No Black
Source GDJ
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
A grayscale fabric pattern with vertical lines of stitch holes.
Source V. Hartikainen
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
An alternative colour scheme to the original seamless pattern.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
Remixed from an image that was uploaded to Pixabay by CatherineClennan
Source Firkin