Related icons are the icons with matching tags, as well as all programming icons
. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors
Idea of PHP Icon
It's a black unfilled square with slightly rounded corners. The radii of the rounded corners is very small. In the center of the square there are the letters "PHP" in upper case.
This page shows the different variations of the PHP from an Icons8 icon pack. Feel free to resize and recolor the icon, and then download the icon in PNG format for free.