Napalm was usually dropped from helicopters in a bomb form. It was used by the U.S and was a highly flammable substance.
Grenades were basically handheld bombs. The Vietcong commonly used them in traps.
Agent orange the chemical used by the U.S to clear a highly planted area. The U.S has since banned it.
The Bayonet was commonly used in older battles but were still seen in the Vietnam war. They were used in close fighting situations or if soldiers were running low on ammo.
Machine guns are commonly used in most wars since they can fire hundreds of rounds a minute.
Since tanks were invented they are used more and more as they are safe armored vehicles.
Helicopters were highly used for transportation, gunners, to drop bombs, and for medical usages.