There are melee weapons, pistols, revolvers, shotguns, sub-machine guns, rifles, automatic rifles, machine guns and sniper guns. Each category has few types and these are varied with mods and skins.
Also important note is that the weapons are consumables - so when you lose a heister, you lost that weapon too.
Players can also have equipment - which are items of fast usage such as grenades, throwing knives, shurikens, rocks, bombs etc.