There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Prismatic Curved Diamond Pattern 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 image depicts a Japanese Edo pattern called "kanoko or 鹿の子" meaning "fawn" which has a fur with small white spots.
Source Yamachem
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Actually remixed from a pattern on Pixabay. But then noticed a very similar one on Openclipart.org uploaded by btj51q2.
Source Firkin
From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
Pass parameters to the URL or edit the source code variables to configure the graph paper for the division desired.
Source JayNick
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A new take on the black linen pattern. Softer this time.
Source Atle Mo
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
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