The most widely used non metal in my opinion is oxygen which is used in :
- combustion
- rockets as fuel.
- graphite is used in pencils and making electrodes because it is not very reactive and can conduct electricity.
- Sulfur is used in making black gunpowder, matches, and fireworks.
- Chlorine can be used
- as a bleaching agent in the presence of moisture.
- Bromine is used in making of pesticides and fire retardants