[T.B. Yoits]

Don't leave out Julio González, who murdered 87 people in a club in the Bronx, New York, in 1990 using a can of gasoline.

https://en.wikipedia.org/wiki/Happy_Land_fire

[Ruy Dias de Bivar]

Yep. We can also add Juan Corona to that who murdered lots of migrant workers in Yuba City Cal back in the 1970a. There is no end of mass murders done with minimal weapons.
Think of Arkansas Ronald Gene Simmons Sr. who murdered 14 members of his own family by strangling them, then using a Ruger single action six shot pistol to kill others.
Where there is a will there is a way.