Here is a shader that draws a simple 2D grid.
Article:
http://www.geeks3d.com/hacklab/20180611/demo-simple-2d-grid-in-glsl/
Downloads:
http://www.geeks3d.com/geexlab/downloads/
(http://www.geeks3d.com/public/jegx/2018q2/geexlab-2d-grid-glsl-demo-01.png)