Type icon theme, choose Preferences: File Icon Theme, and select one of the Material Theme Icons variants from the list. After activation, the icons will appear in your explorer sidebar.
Fix File Icons
If you notice that the folder icons do not match the active Material Theme variant, you can fix it with just a command.
Type material theme icons and select Material Theme Icons: Fix icons accent. from the drop-down menu. This command will set the correct icon theme based on your active Material Theme variant (if present).
Suggest new icons
We have a dedicated Discussions board where you can suggest new icons or discuss with other users